CoChat
Sign Up
Cited by 114Schizophrenia research and treatmentBipolar Disorder and TreatmentAutism Spectrum Disorder Research

Developmental Differences Between Schizophrenia and Bipolar Disorder

Open access
Parellada, Mara, Gomez-Vallejo, Sandra, Burdeus, Monica, Arango, Celso·2017·Schizophrenia Bulletin
DOI 10.1093/schbul/sbx126PMC PMC5737496
Open this paper in CoChat — free accountOpen PDF

Abstract

Ample evidence supports a neurodevelopmental origin in some cases of schizophrenia (SZ). More inconsistent information is available for bipolar disorder (BD). We herein review studies with a focus on premorbid (adjustment and functionality) and early developmental milestones that include both SZ and BD patients. A search was performed in the PubMed electronic database, retrieving 619 abstracts; 30 were ultimately included in this systematic review. Eight prospective cohorts, 15 retrospective studies, and 7 studies based on national registries. Psychomotor developmental deviations and general adjustment problems characterize the childhood of subjects later diagnosed with SZ or BD; they are more marked in those later diagnosed with SZ vs BD, earlier onset vs later onset, and psychotic vs nonpsychotic disorders. Cognitive impairment follows a linear risk trend for SZ and a U-shaped trend for BD. Social isolation and visuoperceptual/reading anomalies more frequently antecede SZ. Pervasive developmental disorders increase the risk for both SZ and BD, more so in cases with normal intelligence. The predictive risk of each isolated developmental marker is low, but a significant percentage of subjects with SZ and a minority of adults with BD showed signs of premorbid abnormalities in childhood. The great limitation is still the lack of studies comparing SZ and BD that include psychotic and nonpsychotic bipolar cases separately. There are many cases, even in childhood/adolescent SZ, where no premorbid anomalies are found, and immunological disorders or other etiologies should be searched for. At least in cases with clear neurodevelopmental markers, rare genetic variants should be investigated.

AI snapshot

Written from the paper’s full text.

TL;DR

This systematic review compares premorbid developmental and adjustment markers in schizophrenia (SZ) and bipolar disorder (BD), finding that childhood psychomotor deviations and adjustment problems occur in both but are generally more prominent in SZ. Cognitive risk patterns differ, with a linear trend for SZ and a U-shaped relationship for BD.

Key findings

  • Across 30 included studies (8 prospective cohorts, 15 retrospective studies, 7 national-registry studies), premorbid psychomotor deviations and general adjustment difficulties were more marked in later SZ than later BD, in earlier-onset than later-onset cases, and in psychotic than nonpsychotic disorders.
  • Cognitive findings diverged: lower childhood IQ predicted SZ-spectrum risk (each 1-SD increase in childhood IQ was linked to a 42% lower odds of lifetime SZ-spectrum diagnosis), while BD showed a U-shaped school-performance pattern (low grades about 2-fold risk; very high grades about 4-fold risk). In one cohort, below-average IQ at age 18 conferred a 3% risk of SZ, and among children not speaking words at age 1, only 0.88% later developed SZ.
  • Social isolation and visuoperceptual/reading anomalies more often preceded SZ. Autism spectrum disorder increased risk for both nonaffective psychosis and BD (5.6 and 5.8 times higher than controls, respectively), with stronger risk in ASD without intellectual disability.
  • Individual developmental markers had low predictive value. Even in early-onset SZ, fewer than half showed premorbid abnormalities; one sample reported broadly impaired social development in 34%, and another reported any delayed milestone in 27% of severely ill hospitalized adolescents with SZ.

Methods

  • Systematic review using a PubMed search on June 17, 2017, retrieving 619 abstracts; 41 were selected for full review, 23 more came from reference lists, 64 were fully reviewed, and 30 were included.
  • Inclusion required studies with both SZ and BD in the population and structured or semistructured assessment of psychomotor milestones, premorbid general/social adjustment, educational attainment, premorbid cognition, or learning difficulties. No publication-year limit was set; English, German, French, and Spanish articles were eligible.
  • Data extraction covered study design, sample characteristics, premorbid assessment, outcome measures, and main findings; two authors reviewed abstracts and two independently reviewed full texts.

Limitations

  • The authors state that the main limitation is the scarcity of studies directly comparing SZ and BD while separating psychotic from nonpsychotic bipolar cases. They also note that ideal prospective unselected cohorts are constrained by low psychosis prevalence, changing nosology, assessment-instrument availability, limited follow-up duration, and attrition that is not independent of diagnosis.
  • Stated retrospective-study limitations include recall bias, selection bias toward hospitalized and more severe patients, and the fact that most included bipolar patients had psychotic BD. Assessment limitations include variability in premorbid adjustment and cognition measures, use of the PAS (designed for SZ) in BD, self-report PAS during acute decompensation, school grades as an imperfect proxy for cognition, and cognitive testing too close to illness onset in some studies.
  • The text also makes evident additional concerns: several included samples had very small BD or mania subgroups, diagnostic systems and instruments varied across studies, and the authors explicitly raise possible information bias or a Pygmalion effect in which current diagnosis may influence retrospective assessment of premorbid problems.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1093/schbul/sbx126

Cites

69 of 69 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 158 cited sources checked · 0 supported · 0 flagged

  • Findingnone given

    Those childhood deviations and adjustment problems are more marked in earlier-onset than later-onset cases.

    “Psychomotor developmental deviations and general adjustment problems characterize the childhood of subjects later diagnosed with SZ or BD; they are more marked in those later diagnosed with SZ vs BD, earlier onset vs later onset, and psychotic vs nonpsychotic disorders.”
    Quote in the paperSubstantial claim
  • Findingown data

    Those childhood deviations and adjustment problems are more marked in later schizophrenia than in later bipolar disorder.

    “Psychomotor developmental deviations and general adjustment problems characterize the childhood of subjects later diagnosed with SZ or BD; they are more marked in those later diagnosed with SZ vs BD, earlier onset vs later onset, and psychotic vs nonpsychotic disorders.”
    Quote in the paperSubstantial claim
  • Findingreasoning

    Among adults with bipolar disorder, a minority have childhood premorbid abnormality signs.

    “The predictive risk of each isolated developmental marker is low, but a significant percentage of subjects with SZ and a minority of adults with BD showed signs of premorbid abnormalities in childhood.”
    Quote in the paperSubstantial claim
  • Findingnone given

    Even in child or adolescent schizophrenia, many cases show no premorbid anomalies.

    “There are many cases, even in childhood/ adolescent SZ, where no premorbid anomalies are found, and immunological disorders or other etiologies should be searched for.”
    Quote in the paperSubstantial claim
  • Findingnone given

    The increased risk from pervasive developmental disorders is greater in cases with normal intelligence.

    “Pervasive developmental disorders increase the risk for both SZ and BD, more so in cases with normal intelligence.”
    Quote in the paperSubstantial claim
  • May combine two claims. 56
  • Classified as probably not a substantial claim. 18

  • May combine two claims.

    Findingnone given

    Social isolation and visuoperceptual/reading anomalies more frequently precede schizophrenia.

    “Social isolation and visuoperceptual/reading anomalies more frequently antecede SZ.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    In schizophrenia, cognitive and adjustment impairments occur at first psychosis, in high-risk people, and in early infancy before clinical high risk is evident.

    “Cognitive and (adjustment to the environment) impairments in SZ are present in coincidence with the first time psychotic symptoms appear, but also in high-risk subjects and even in early infancy, before the clinical high-risk state is apparent.[9][10][11]”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [9] 1998, Neurocognitive deficit in schizophrenia: a quantitative review of the evidence, Neuropsychology source

      Not checked in the free run.

    • cites [10] 2015, Cognition in at-risk mental states for psychosis, Neurosci Biobehav Rev source

      Not checked in the free run.

    • cites [11] 2004, A developmental model for similarities and dissimilarities between schizophrenia and bipolar disorder, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Later studies fairly consistently found premorbid abnormalities and cognitive performance more affected in schizophrenia than affective psychosis.

    “Subsequent studies with a wide range of sample sizes (73-266) have shown quite consistently that, in hospitalized patients, premorbid abnormalities (most frequently assessed with the Cannon-Spoor Premorbid Adjustment Scale, PAS 33 ) or cognitive performance are more marked in SZ than in affective psychosis.17,[34][35][36][37][38][39][40][41][42][43][44]”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [17] 2010, Excellent school performance at age 16 and risk of adult bipolar disorder: national cohort study, Br J Psychiatry source

      Not checked in the free run.

    • cites [34] 2002, The relationship between predisposing factors, premorbid function and symptom dimensions in psychosis: an integrated approach, Eur Psychiatry source

      Not checked in the free run.

    • cites [35] 1991, Low birth weight and a family history of schizophrenia predict poor premorbid functioning in psychosis, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Findingnone given

    Developmental pathology in bipolar disorder tends to have early onset and is usually less severe than in schizophrenia.

    “Developmental pathology in bipolar disorder (BD) is associated with early onset and is generally milder than observed in SZ.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Higher IQ was linked to mania risk, though the sample was very small.

    “Again, lower childhood IQ predicted more risk of a SZ spectrum disorder (as well as other disorders); for each standard deviation increase in childhood IQ, the participants had a 42% reduction in the odds of a lifetime SZ spectrum diagnosis; higher IQ was associated with risk for mania (albeit very small sample).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] 2009, Childhood IQ and adult mental disorders: a test of the cognitive reserve hypothesis, Am J Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The PubMed review retrieved 619 articles.

    “Our PubMed review retrieved 619 articles.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    For bipolar disorder the risk pattern was quadratic; very high performers (over 2 SD) had a 4-fold risk increase.

    “A quadratic relationship was observed for BD, with Development in Schizophrenia and Bipolar Disorder pupils at the higher end of performance (over 2 SD of the mean) having a 4-fold increased risk.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [17] 2010, Excellent school performance at age 16 and risk of adult bipolar disorder: national cohort study, Br J Psychiatry source

      Not checked in the free run.

    • cites [18] 2008, Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study, Psychol Med source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Nothing distinguished schizophrenia from other psychoses; speech delay emerged only after combining schizophrenia with other psychosis groups.

    “No finding was specific to SZ compared with other psychoses, and in fact, speech delay only appeared when SZ and other psychosis groups were combined.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [19] 2001, Early developmental milestones in adult schizophrenia and other psychoses. A 31-year follow-up of the Northern Finland 1966 Birth Cohort, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Interpersonal problems in early life were strongly linked to later schizophrenia and less so to non-schizophrenia psychosis.

    “Early problems in interpersonal relationships were strongly associated with later SZ and, to a lesser extent, with non-SZ psychosis.28”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [28] 1998, Premorbid adjustment and personality in people with schizophrenia, Br J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Lower cognitive function at ages 12 and 18 was linked to schizophrenia (more strongly at 18) and bipolar disorder.

    “Cognitive function at ages 12 and 18 was inversely associated with SZ (stronger for the 18-year assessment) and BD.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [26] 2007, Cognitive function in childhood and early adulthood and hospital admission for schizophrenia and bipolar disorders in Danish men born in 1953, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Infant receptive language and cognitive deficits predicted schizophreniform disorders, not mania.

    “Receptive language and cognitive impairments throughout infancy also predicted schizophreniform disorders, but not mania (as compared with the control outcome group).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [20] 2002, Evidence for early-childhood, pan-developmental impairment specific to schizophreniform disorder: results from a longitudinal birth cohort, Arch Gen Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    The Swedish Conscript Study found adolescent IQ below average in both schizophrenia and other psychosis, with schizophrenia more affected.

    “The Swedish Conscript Study, with a larger sample of 195 subjects with SZ and 193 with other psychosis, reported below average IQ in adolescents in both groups of patients, more marked again in SZ. 28”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [28] 1998, Premorbid adjustment and personality in people with schizophrenia, Br J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    The study did not separate psychotic from nonpsychotic bipolar disorder, nor schizophrenia from unspecified nonaffective psychosis.

    “No distinction was made in the outcomes for psychotic (9.8% of the BD sample) and nonpsychotic BD or for SZ or unspecified nonaffective psychosis (45.6% of the NAP sample).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] 2015, Risks for nonaffective psychotic disorder and bipolar disorder in young people with autism spectrum disorder: a population-based study, JAMA Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    In males, failure to walk or speak by age 1, and in females, failure to be potty trained at that age, were linked to later psychosis.

    “Not walking and/or not speaking at year 1 in males and not being potty trained at that same age in females was associated with a psychotic outcome in the sample of 81 patients with both assessments.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [19] 2001, Early developmental milestones in adult schizophrenia and other psychoses. A 31-year follow-up of the Northern Finland 1966 Birth Cohort, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Later schizophrenia was distinguished from controls and nonpsychotic bipolar by poorer premorbid intellect, reading problems, and more behavioral disturbance.

    “Subjects later diagnosed with SZ differed from healthy control subjects and from nonpsychotic bipolar subjects in having worse premorbid intellectual abilities and reading difficulties and more behavioral disturbances.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [30] 2002, A population-based cohort study of premorbid intellectual, language, and behavioral functioning in patients with schizophrenia, schizoaffective disorder, and nonpsychotic bipolar disorder, Am J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Childhood delayed motor and language milestones, schizoid social functioning, and poor school achievement were precursors of schizophrenia.

    “Developmental precursors of SZ included childhood delayed motor and language milestones, schizoid social functioning, and poor educational achievement; different patterns of maladjustment were present in boys and girls at the 7 and 11 year evaluations, with an un-reactive and an over-reactive type, respectively.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [23] 1994, Child development risk factors for adult schizophrenia in the British 1946 birth cohort, Lancet source

      Not checked in the free run.

    • cites [24] 1997, Developmental precursors of affective illness in a general population birth cohort, Arch Gen Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Both groups deteriorated during adolescence, more so in schizophrenia.

    “Both patient groups showed a deteriorating course in adolescence, greater in SZ patients.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [37] 1997, Premorbid social functioning in schizophrenia and bipolar disorder: similarities and differences, Am J Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Thirty of the 64 studies reviewed in full were included.

    “Of the 64 finally fully reviewed studies, 30 studies were finally selected for inclusion in this study.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    In an ASD cohort, nonaffective psychosis risk was 5.6 times and bipolar risk 5.8 times that of healthy controls.

    “The risk of a diagnosis of nonaffective psychosis (NAP) or BD in the ASD group was, respectively, 5.6 and 5.8 times greater than in healthy controls, with an even greater risk for those diagnosed with ASD without intellectual disability (ID).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] 2015, Risks for nonaffective psychotic disorder and bipolar disorder in young people with autism spectrum disorder: a population-based study, JAMA Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Poor school performance raised schizophrenia risk 2- to 4-fold and bipolar risk about 2-fold.

    “Subjects with a lower level of performance had increased risk for SZ (2-to 4-fold) and a moderately increased risk (2-fold) for BD.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [17] 2010, Excellent school performance at age 16 and risk of adult bipolar disorder: national cohort study, Br J Psychiatry source

      Not checked in the free run.

    • cites [18] 2008, Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study, Psychol Med source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Cannon et al. found schizophrenia patients scored worse than controls and psychotic bipolar patients, while bipolar patients scored worse than controls.

    “Cannon et al 37 reported that SZ patients scored significantly worse than normal controls and psychotic bipolar patients, and the latter scored worse than controls.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [37] 1997, Premorbid social functioning in schizophrenia and bipolar disorder: similarities and differences, Am J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    A later analysis found a linear IQ-schizophrenia risk relationship, but no IQ-bipolar association.

    “In a later analysis of this same register, now with n = 50 053, including 362 who had developed SZ and 108 BD, IQ seemed to have a linear relationship with risk of SZ. 29 No association was found with BD.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [29] 2004, A longitudinal study of premorbid IQ Score and risk of developing schizophrenia, bipolar disorder, severe depression, and other nonaffective psychoses, Arch Gen Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Before age 18, ADHD was diagnosed in 1.1% of schizophrenia and 0.7% of bipolar patients; conduct disorder in 1.1% and 2%.

    “Only 1.1% and 0.7% of patients with SZ and BD, respectively, had a diagnosis of ADHD before age 18, and only 1.1% and 2% had a diagnosis of conduct disorder before age 18.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] 2013, Preceding diagnoses to young adult bipolar disorder and schizophrenia in a nationwide study, BMC Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Premorbid social adjustment strongly predicted later social functioning in both disorders and was a good, though not exclusive, predictor of schizophrenia diagnosis.

    “Premorbid social adjustment (for the most part impaired social functioning was already present in childhood) was a strong predictor of social functioning in both SZ and BD and was a good (but not exclusive) predictor of a SZ diagnosis.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [45] 2016, The 20-year longitudinal trajectories of social functioning in individuals with psychotic disorders, Am J Psychiatry

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Compared with other psychosis patients, schizophrenia patients more often had delayed urinary competence and worse premorbid social functioning.

    “SZ patients more frequently had delayed urinary competence and had more impairment in premorbid social functioning than other psychosis patients; no difference was found between SZ patients and other-psychosis patients in any motor, language, or reading indicators (although there was not a separate analysis for affective psychosis within the other-psychosis group).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [40] 2003, Developmental precursors of child- and adolescent-onset schizophrenia and affective psychoses: diagnostic specificity and continuity with symptom dimensions, Br J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Across diagnoses, many patients had stable low-average premorbid functioning; schizophrenia patients more often had impaired trajectories, mood disorder patients better ones.

    “In the latter two studies, there was low average premorbid functioning that remained stable in a significant number of patients across diagnoses; more patients with SZ disorders had impaired trajectories and more with mood disorders had better functioning trajectories.45,46”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [45] 2016, The 20-year longitudinal trajectories of social functioning in individuals with psychotic disorders, Am J Psychiatry

      Not checked in the free run.

    • cites [46] 2015, Functional deterioration from the premorbid period to 2 years after the first episode of psychosis in early-onset psychosis, Eur Child Adolesc Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Social outcomes were worse in schizophrenia spectrum disorders, and long-term social impairment after onset was remarkably stable across diagnoses.

    “Overall, there were worse social outcomes in SZ spectrum disorders and remarkably stable longterm impairments in social functioning after illness onset across all diagnoses.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [45] 2016, The 20-year longitudinal trajectories of social functioning in individuals with psychotic disorders, Am J Psychiatry

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    For adjustment up to age 15, both groups were worse than controls in all areas and declined from childhood.

    “With regard to early adolescent adjustment (up to 15 years of age), both groups performed worse than controls in all areas and both showed a decline from childhood.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [41] 2013, Premorbid impairments in early-onset psychosis: differences between patients with schizophrenia and bipolar disorder, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Urinary incompetence, poor premorbid functioning, and negative symptoms were continuous.

    “Continuity was found between urinary incompetence, poor premorbid functioning, and a negative dimension.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [40] 2003, Developmental precursors of child- and adolescent-onset schizophrenia and affective psychoses: diagnostic specificity and continuity with symptom dimensions, Br J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Some risk factors may be shared by the two disorders, while others may cause schizophrenia to be more severe.

    “The 2 disorders may share some risk factors while others may lead to the greater severity in SZ. 1,11”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [1] 2014, Differential neurodevelopmental trajectories in patients with early-onset bipolar and schizophrenia disorders, Schizophr Bull source

      Not checked in the free run.

    • cites [11] 2004, A developmental model for similarities and dissimilarities between schizophrenia and bipolar disorder, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The literature does not clearly establish whether a larger proportion of schizophrenia patients than bipolar patients have premorbid abnormalities or whether premorbid abnormalities are more severe in schizophrenia.

    “First, the literature does not make it clear enough whether a larger Development in Schizophrenia and Bipolar Disorder proportion of SZ patients than bipolar patients do have premorbid abnormalities or if premorbid abnormalities are more severe in SZ.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    When directly compared, neurodevelopmental deviations (including neuromotor and cognitive impairment) are present in both schizophrenia and bipolar disorder, but more strongly and extensively in schizophrenia.

    “When directly compared, neurodevelopmental deviations (including neuromotor and cognitive impairment) are shown in both SZ and BD, but more strongly and extensively in the former.17,18,20,22,25,28”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [17] 2010, Excellent school performance at age 16 and risk of adult bipolar disorder: national cohort study, Br J Psychiatry source

      Not checked in the free run.

    • cites [18] 2008, Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study, Psychol Med source

      Not checked in the free run.

    • cites [20] 2002, Evidence for early-childhood, pan-developmental impairment specific to schizophreniform disorder: results from a longitudinal birth cohort, Arch Gen Psychiatry source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Because of the low prevalence of psychosis, the number of patients who end with a diagnosis of schizophrenia or bipolar disorder in the follow-up time of these cohorts is usually not large.

    “In addition, because of the low prevalence of psychosis, the number of patients who end with a diagnosis of SZ or BD in the follow-up time of these cohorts is usually not large.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    In Reichenberg et al.'s comparison study, schizophrenia patients performed worse than nonpsychotic bipolar patients on all cognitive measures, and bipolar patients did not differ from control subjects.

    “Reichenberg et al 30 included only nonpsychotic affective disorders in their comparison study with SZ and found that the latter performed worse in all cognitive measures and bipolar patients did not differ from control subjects.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [30] 2002, A population-based cohort study of premorbid intellectual, language, and behavioral functioning in patients with schizophrenia, schizoaffective disorder, and nonpsychotic bipolar disorder, Am J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductcitation

    That cohort did not present a direct comparison between patient groups, and its mania group sample size was limited (n = 20).

    “but no direct comparison between patient groups was presented and the sample size of the mania group was quite limited (n = 20).20”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [20] 2002, Evidence for early-childhood, pan-developmental impairment specific to schizophreniform disorder: results from a longitudinal birth cohort, Arch Gen Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Patients with bipolar disorders may have childhood and adolescent maladjustment but not cognitive impairment or poor academic performance.

    “In general, it seems that patients with BDs may have childhood and adolescent maladjustment but not cognitive impairment or bad academic performance.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    A cohort with detailed developmental assessment over infancy found clear differences between later schizophrenia patients and controls, and no differences between the future bipolar group and controls.

    “One of the cohorts with a more detailed developmental assessment over the course of infancy reported clear differences between patients later diagnosed with SZ compared with control subjects and no differences between the future bipolar group and controls”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [20] 2002, Evidence for early-childhood, pan-developmental impairment specific to schizophreniform disorder: results from a longitudinal birth cohort, Arch Gen Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Deterioration of visual information acquisition and processing has been postulated to contribute to higher-order cognitive dysfunctions and ultimately to schizophrenia symptoms.

    “Deterioration of visual information acquisition and processing has been postulated to contribute to higher-order cognitive dysfunctions and ultimately to SZ symptoms, 58 signaling another possible pathway to psychotic symptoms.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [58] 2013, “To see or not to see: that is the question.” The “Protection-Against-Schizophrenia” (PaSZ) model: evidence from congenital blindness and visuo-cognitive aberrations, Front Psychol

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Schizophrenia and bipolar disorder are better thought of as clinical syndromes rather than disorders.

    “These data highlight the idea that SZ and BD are better thought of as clinical syndromes rather than disorders.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    When compared with controls, early-onset schizophrenia patients show more social withdrawal, and bipolar patients show a trend for general social premorbid difficulties.

    “when patients are compared with control subjects, 41 SZ patients do show more social withdrawal than the former, and bipolar patients also show a trend for general social premorbid difficulties.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [41] 2013, Premorbid impairments in early-onset psychosis: differences between patients with schizophrenia and bipolar disorder, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Most retrospective studies include hospitalized psychotic patients and generally show that schizophrenia patients have poor premorbid adjustment, while bipolar disorder patients have either no premorbid maladjustment or an adjustment intermediate between schizophrenia and healthy controls.

    “Most retrospective studies include hospitalized psychotic patients and generally show that patients with SZ have poor premorbid adjustment and that BDs have either no premorbid maladjustment or an adjustment that is intermediate between SZ and healthy controls.20,38,42,43”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [20] 2002, Evidence for early-childhood, pan-developmental impairment specific to schizophreniform disorder: results from a longitudinal birth cohort, Arch Gen Psychiatry source

      Not checked in the free run.

    • cites [38] PEPs Group, 2015, Premorbid adjustment and clinical correlates of cognitive impairment in first-episode psychosis. The PEPsCog Study, Schizophr Res source

      Not checked in the free run.

    • cites [42] 2006, Premorbid adjustment in bipolar disorder: comparison with schizophrenia, J Nerv Ment Dis source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Findings from retrospective studies tend to report a greater magnitude of prevalence of premorbid abnormalities in schizophrenia than prospective studies, though similar.

    “Although similar to those of prospective studies, findings from retrospective studies tend to report a greater magnitude of the prevalence of premorbid abnormalities in SZ.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Reading abilities seem to characterize the childhood of subjects later diagnosed with schizophrenia, in addition to general intellectual functioning difficulties.

    “In addition to general intellectual functioning difficulties, reading abilities seem to characterize the childhood of subjects who are later diagnosed with SZ.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [30] 2002, A population-based cohort study of premorbid intellectual, language, and behavioral functioning in patients with schizophrenia, schizoaffective disorder, and nonpsychotic bipolar disorder, Am J Psychiatry source

      Not checked in the free run.

    • cites [40] 2003, Developmental precursors of child- and adolescent-onset schizophrenia and affective psychoses: diagnostic specificity and continuity with symptom dimensions, Br J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In the North Finland Birth Cohort, among children not speaking words at age 1, only 0.88% developed schizophrenia, a statistically significant but low risk.

    “the North Finland Birth Cohort study 19 showed that, of all children not speaking words at 1 year of age, only 0.88% would develop SZ (a statistically significant difference, but a low risk)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [19] 2001, Early developmental milestones in adult schizophrenia and other psychoses. A 31-year follow-up of the Northern Finland 1966 Birth Cohort, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Few studies separate nonpsychotic bipolar disorder from other bipolar disorders, making findings difficult to summarize.

    “The findings with regard to nonpsychotic BD are more difficult to sum up as few studies separate those from other BDs.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    The mechanisms underlying the relationship between premorbid impairments and schizophrenia/bipolar disorder are likely a mixture of common etiologies, cognitive mechanisms, independent risk factors, reverse causality, and/or residual confounding.

    “The mechanisms underlying the relationship between premorbid impairments and SZ/BD are likely a mixture of the following: (1) common etiologies (genetic and/or environmental), (2) cognitive mechanisms whereby cognitive difficulties drive social difficulties in adjustment to the environment and reality testing 53”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [53] 2006, Cognitive reserve in neuropsychiatry, Psychol Med source

      Not checked in the free run.

    • cites [34] 2002, The relationship between predisposing factors, premorbid function and symptom dimensions in psychosis: an integrated approach, Eur Psychiatry source

      Not checked in the free run.

    • cites [26] 2007, Cognitive function in childhood and early adulthood and hospital admission for schizophrenia and bipolar disorders in Danish men born in 1953, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Social isolation and cognitive performance decline before illness onset are more clearly associated with schizophrenia.

    “Two aspects have been more clearly associated with SZ, ie, social isolation (while other types of social maladjustment are also present in children diagnosed with psychotic BD later in life) and cognitive performance decline before illness onset.26,30,45”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [26] 2007, Cognitive function in childhood and early adulthood and hospital admission for schizophrenia and bipolar disorders in Danish men born in 1953, Schizophr Res source

      Not checked in the free run.

    • cites [30] 2002, A population-based cohort study of premorbid intellectual, language, and behavioral functioning in patients with schizophrenia, schizoaffective disorder, and nonpsychotic bipolar disorder, Am J Psychiatry source

      Not checked in the free run.

    • cites [45] 2016, The 20-year longitudinal trajectories of social functioning in individuals with psychotic disorders, Am J Psychiatry

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Worse premorbid adjustment is associated with cognition after a first episode, with deterioration, and with negative symptoms, signaling a poor-outcome subgroup of schizophrenia.

    “Worse adjustment has been shown to be associated with cognition 38 after a first episode and also with deterioration 43 and with negative symptoms, 37 signaling a bad outcome subgroup of SZ.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [38] PEPs Group, 2015, Premorbid adjustment and clinical correlates of cognitive impairment in first-episode psychosis. The PEPsCog Study, Schizophr Res source

      Not checked in the free run.

    • cites [43] 1996, Demographics, family history, premorbid functioning, developmental characteristics, and course of patients with deteriorated affective disorder, Am J Psychiatry source

      Not checked in the free run.

    • cites [37] 1997, Premorbid social functioning in schizophrenia and bipolar disorder: similarities and differences, Am J Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Clinicians may be inclined toward a diagnosis of schizophrenia in the presence of abnormal premorbid adjustment, due to the neurodevelopmental hypothesis.

    “In the last few decades, as authors started to identify neurodevelopmental problems in the infancies of patients with SZ and preeminent experts have considered this a neurodevelopmental disorder, at least in some cases, clinicians may be inclined toward a diagnosis of SZ in the presence of abnormal premorbid adjustment.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationreasoning

    As patients age and face more independent life demands, the gap with peer functioning may widen, leading to the downward shift detected in many studies.

    “Once patients get older and need to operate in a more independent and therefore challenging type of life, separated from family protection, the gap with peer functioning may get larger, leading to the downward shift detected in many studies.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Most subjects with developmental anomalies will not develop schizophrenia.

    “As most subjects with developmental anomalies will not end up having SZ”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    A U-shaped effect better explains the relationship between IQ and bipolar disorders, with above-average cognitive performance increasing risk more than low IQ.

    “a U-shaped effect better explains the relationship between IQ and BDs; aboveaverage cognitive performance increases the risk even more than low IQ. 17”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [17] 2010, Excellent school performance at age 16 and risk of adult bipolar disorder: national cohort study, Br J Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Some type of language disorder may be part of the same phenomenon later expressed as reality distortion.

    “That some type of language disorder may be part of the same phenomenon that is later expressed in the form of reality distortion is a long-held idea.56,57”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [56] 1995, Childhood precursors of psychosis as clues to its evolutionary origins, Eur Arch Psychiatry Clin Neurosci source

      Not checked in the free run.

    • cites [57] 2006, Continuities and discontinuities in psychopathology between childhood and adult life, J Child Psychol Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Low intelligence is associated with increased risk of schizophrenia and other psychoses.

    “This result contrasts with the well-documented fact that low intelligence is associated with increased risk of SZ and other psychoses.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A recent review and meta-analysis reported a prevalence of 8% of anti-NMDA receptor antibody positivity in patients with psychosis.

    “A recent review and meta-analysis has reported a prevalence of 8% of anti-NMDA receptor antibody positive in patients with psychosis.52”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [52] 2013, Preventing a first episode of psychosis: meta-analysis of randomized controlled prevention trials of 12 month and longer-term follow-ups, Schizophr Res source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Individual developmental markers can have pluripotential outcomes, and the same outcome can have different pathways leading to it, analogous to pleiotropic effects of single risk genes.

    “In the same vein as single risk genes have pleiotropic effects leading to diverse outcomes and similar outcomes can be associated with different risk genes, individual developmental markers can have pluripotencial outcomes and same outcome can have different pathways that lead to it.62,63”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [62] 2015, The Philadelphia Neurodevelopmental Cohort: constructing a deep phenotyping collaborative, J Child Psychol Psychiatry source

      Not checked in the free run.

    • cites [63] 2006, Clinical staging of psychiatric disorders: a heuristic framework for choosing earlier, safer and more effective interventions, Aust N Z J Psychiatry source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The findings of these studies support the absence of a categorically distinct diagnosis, but the existence of different developmental marker-symptomatic domain dimensions.

    “The findings of these studies clearly support the absence of a categorically distinct diagnosis, but somehow the existence of different (developmental marker-symptomatic domain) dimensions.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductcitation

    Very few studies have used direct and contemporary assessments of cognitive functioning; many others have used scholastic attainment as a proxy for cognitive impairment.

    “With regard to cognitive performance, very few studies have used direct and contemporary assessments of cognitive functioning 17,18,20 ; many others have used scholastic attainment as a proxy of cognitive impairment”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [17] 2010, Excellent school performance at age 16 and risk of adult bipolar disorder: national cohort study, Br J Psychiatry source

      Not checked in the free run.

    • cites [18] 2008, Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study, Psychol Med source

      Not checked in the free run.

    • cites [20] 2002, Evidence for early-childhood, pan-developmental impairment specific to schizophreniform disorder: results from a longitudinal birth cohort, Arch Gen Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Self-report PAS has occasionally been used at the time of a psychotic decompensation.

    “Occasionally, 42 self-report PAS has been used at the time of a psychotic decompensation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] 2006, Premorbid adjustment in bipolar disorder: comparison with schizophrenia, J Nerv Ment Dis source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Great efforts are being made in some exceptional settings to identify and treat markers of deviant development or early symptoms with the hope of preventing major disorders or reducing associated disability.

    “Great efforts are been made in some exceptional settings to identify and treat markers of deviant development or early symptoms with the hope that this will prevent major disorders to appear or reduce associated disability.63”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [63] 2006, Clinical staging of psychiatric disorders: a heuristic framework for choosing earlier, safer and more effective interventions, Aust N Z J Psychiatry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The account of past adjustment can be biased by present symptomatology.

    “The account of past adjustment can clearly be biased by present symptomatology.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    These developmental pathologies vary within schizophrenia and bipolar disorders and tend to be more severe and/or common in schizophrenia.

    “These pathologies vary within SZ and BDs and tend to be more severe and/or common in SZ.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Study design and conductnone given

    School grades may partially reflect political and social laws and practices in addition to pupils' abilities.

    “school grades may partially reflect political and social laws and practices in addition to pupils' abilities.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based). May combine two claims.

    Interpretationnone given

    These pathologies provide a critical roadmap for the study of causal pathways and provide clinicians with important prognostic information.

    “They provide a critical roadmap for the study of causal pathways and provide clinicians with important prognostic information.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Some data is being gathered on treating high-risk prodromal states to prevent transition to psychosis, still with limited results.

    “Some data is being gathered with respect to treating high-risk prodromic states to prevent transition to psychosis 52 still with limited results.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [52] 2013, Preventing a first episode of psychosis: meta-analysis of randomized controlled prevention trials of 12 month and longer-term follow-ups, Schizophr Res source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationnone given

    The developmental psychopathology perspective taken in the reviewed studies shows the changing picture of clinical manifestations.

    “The developmental psychopathology perspective taken in the studies herein reviewed shows the changing picture of the clinical manifestations.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductnone given

    Longitudinal studies have limitations: duration not long enough to cover the whole age range for appearance of psychotic disorders, and attrition rate is not independent of diagnosis.

    “The duration of longitudinal studies, not long enough to include the whole age range for appearance of psychotic disorders and the attrition rate (which is not independent of diagnosis) are other limitations.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Study design and conductnone given

    The PAS, the most widely used instrument for premorbid adjustment, was designed for schizophrenia and may not capture different premorbid abnormalities present in bipolar disorder.

    “The most widely used instrument for premorbid adjustment, the PAS, was designed for SZ and may not capture different premorbid abnormalities present in BD.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductnone given

    Retrospective studies have important limitations: recall bias (informants selectively report developmental difficulties in problem subjects), selection bias (most patients are hospitalized and represent a more severe end of the spectrum), and most included bipolar patients have psychotic bipolar disorder.

    “retrospective studies endorse important limitations such as recall bias (informants selectively report developmental difficulties in problem-subjects), selection bias (most patients included in these studies are hospitalized and therefore represent a more severe end of the spectrum), and the fact that most bipolar patients included have psychotic BDs.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Early intervention studies to treat social and behavioral symptoms have proven to change the symptomatic picture, but no study has yet been large enough to prove that these interventions reduce the rate of schizophrenia or bipolar disorder.

    “Early intervention studies to treat social and behavioral symptoms have proven to change the symptomatic picture, but no study has yet been so big to prove that these interventions reduce the rate of SZ or BD.64”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [64] 2017, When the healthcare does not follow the evidence: The case of the lack of early intervention programs for psychosis in Spain, Rev Psiquiatr Salud Ment

      Not checked in the free run.

  • May combine two claims.

    Study design and conductnone given

    Some studies have used cognitive measurements too close to the age of onset of psychotic disorders, and other studies have used premorbid intelligence at the time of recruitment (the latter were not included in this review).

    “some studies have used cognitive measurements too close to the age of onset of psychotic disorders (the studies with conscripts) and a number of other studies have used premorbid intelligence at the time of recruitment (the latter were not included in this review).”
    Quote in the paperNot a substantial claim
71 of 71

  • The paper relies on this without support.

    Information about neurodevelopmental origins in bipolar disorder is more inconsistent than for schizophrenia.

    “More inconsistent information is available for bipolar disorder (BD).”

  • The paper relies on this without support.

    Few studies have examined premorbid abnormalities in both schizophrenia and bipolar disorder within the same study to assess specificity of developmental deviations.

    “However, very few studies have looked at premorbid abnormalities in both disorders in the same study in order to assess the specificity of the predictive value of distinct developmental deviations.”

  • The paper relies on this without support.

    Few available studies have made premorbid adjustment or functioning their main objective.

    “In addition, among the available studies, very few have made premorbid adjustment or functioning their main objective.”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Schizophrenia trajectory percentages cannot form distinct groups

    Major

    The four trajectories are described as distinct, yet the stated schizophrenia percentages add to more than 116.5%: over 20%, 75%, over 20%, and 1.5%.

  • Hollis reading and language findings are reversed

    Minor

    The narrative says schizophrenia and other psychoses did not differ on language or reading indicators. The table instead reports more language and reading delays in schizophrenia.

  • School-grade study is called a direct cognitive assessment

    Minor

    The limitations section cites study 17 as using a direct assessment of cognitive functioning, but the table identifies its premorbid measure as GPA, which the same section distinguishes from direct cognitive assessment.

  • Uzelac schizophrenia sample differs by one patient

    Minor

    The narrative describes 54 schizophrenia patients in a total sample of 93, while the table lists 53 schizophrenia patients and 39 bipolar patients, totaling 92.

  • Cannon study sample sizes disagree

    Minor

    The narrative describes 70 schizophrenia and 28 bipolar patients in the Cannon study. The table gives 100 and 49, respectively, for the South London Cannon study.

  • Swedish conscript comparison-group count differs

    Minor

    The narrative reports 193 people with other psychoses, whereas the corresponding table entry reports 195.

  • Publication-date limit is stated both ways

    Minor

    The methodology says there was no publication-year limit, but the search strategy says articles before 1975 were filtered out.

  • Antibody-prevalence claim cites a prevention-trial review

    Minor

    The cited reference concerns trials to prevent a first episode of psychosis, not the stated meta-analysis of anti-NMDA receptor antibody prevalence.

8 of 8

Cites

Flagged first, then by citations

1 of the 70 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. 2013, Schizophrenia

Cited by

Sorted by citations

Related

Authors
Parellada, M., Gomez-Vallejo, S., Burdeus, M., & Arango, C.
Affiliations
Universidad Complutense de Madrid (ES)
Corresponding author
Parellada, Mara
ORCID
Venue
Schizophrenia Bulletin
Publisher
Oxford University Press (OUP)
Published
2017-10-14
Volume
43
Issue
6
Pages
1176-1189
ISSN
  • 0586-7614 (ISSN-L)
  • 1745-1701
DOI
10.1093/schbul/sbx126
PMC
PMC5737496
OpenAlex
W2763058017
Cited by
114
References
70
Citations by year
2026: 5 · 2025: 9 · 2024: 10 · 2023: 15 · 2022: 20 · 2021: 14 · 2020: 18 · 2019: 13 · 2018: 7 · 2017: 3
FWCI
9.20
Type
journal article
Language
en
Open access
Locations
  • Schizophrenia Bulletin (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, other-oa)
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Schizophrenia research and treatment
  • Health Sciences › Medicine › Psychiatry and Mental health › Bipolar Disorder and Treatment
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Autism Spectrum Disorder Research
Keywords
schizophrenia, bipolar disorder
MeSH terms
Bipolar Disorder, Humans, Human Development, Psychotic Disorders, Schizophrenia, Cognitive Dysfunction

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-06.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-06.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review