Sleep and mental disorders: a meta-analysis of polysomnographic research

Borderline on S4 (based): unclear from the text.

Sleep continuity problems were observed in most mental disorders.

“Sleep continuity problems were observed in most mental disorders.”

Borderline on S1 (asserted), S3 (load-bearing), S4 (based): unclear from the text.

In the absence of comorbidities, major depression was no longer associated with increased REM sleep pressure.

“In the absence of comorbidities, major depression was no longer associated with increased REM sleep pressure.”

May combine two claims.

Comorbidity was associated with enhanced REM sleep pressure and greater inhibition of sleep depth.

“Comorbidity was associated with enhanced REM sleep pressure and more inhibition of sleep depth.”

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

The largest sample for calculations was for REM latency in affective disorders, including 1597 patients and 1178 controls.

“The largest sample available for calculations related to REM latency for affective disorders included 1597 patients and 1178 controls.”

May combine two claims.

The working age adults group was evaluated in the majority of studies, and results for this group did not differ substantially from main results.

“The working age adults group was evaluated in the majority of the studies, thus, the results related to this age group did not differ substantially from the main results.”

May combine two claims.

No sleep alteration was observed in ADHD and seasonal affective disorder, apart from marginally significant shortened TST in seasonal affective disorder.

“Instead, no sleep alteration was observed in ADHD and seasonal affective disorder (apart from marginally significant shortened TST), although analyses for this last condition were limited.”

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

The smallest sample was for Asperger syndrome (34 patients vs 24 controls).

“Instead, analyses for Asperger syndrome (34 patients vs 24 controls) included the smallest sample size.”

May combine two claims.

Panic disorder was linked with poorer sleep efficiency, marginally significant longer sleep onset latency, and shortened total sleep time compared to controls.

“Panic disorder was linked with poorer sleep efficiency, marginally significant longer sleep onset latency and shortened total sleep time compared to controls.”

May combine two claims.

Schizophrenia was associated with alteration of sleep continuity, sleep architecture, and longer REM latency.

“Finally, schizophrenia was associated with alteration of sleep continuity, sleep architecture and longer REM latency.”

May combine two claims.

Patients with autism spent shorter time in REM compared to controls, but did not present alterations in REML or REMD.

“Differently, patients with autism spent shorter time in REM compared to controls, but did not present alterations in REML nor REMD.”

May combine two claims.

In pediatric major depression, no change was found in total sleep time, REMD, and duration of S1 and REM sleep compared to controls.

“Considering specific sleep variables, we found no change in total sleep time, REMD, and duration of S1 and REM sleep compared to controls.”

May combine two claims.

Patients with anxiety disorders, particularly PTSD, presented shortened SWS, but no alterations in duration of S1 and S2.

“Patients with anxiety disorders, and in particular PTSD, presented shortened SWS, but no alterations in duration of S1 and S2.”

May combine two claims.

Neither patients with anorexia nervosa nor with borderline personality disorder spent more time to fall asleep than controls.

“Nevertheless, neither patients with anorexia nervosa nor with borderline personality disorder spent more time to fall asleep than controls.”

May combine two claims.

In depression, sleep continuity and depth, as well as REM pressure, were all altered in male patients compared to controls, while in female samples only sleep continuity was disturbed.

“With respect to depression, sleep continuity and depth, as well as REM pressure were all altered in male patients compared to controls, while in female samples only sleep continuity was found to be disturbed.”

May combine two claims.

Asperger syndrome was not associated with alterations of sleep architecture and REM, while autistic patients spent reduced time in REM sleep.

“Within pervasive developmental disorders, Asperger syndrome was not associated with alterations of sleep architecture and REM, while autistic patients spent reduced time in REM sleep.”

May combine two claims.

REM sleep variables were all altered only in men with depression, and not in women, for whom only a marginally significant increased REMD was noted.

“REM sleep variables (REM latency, REM density and REM sleep duration) were all altered only in men with depression, and not in women, for whom only a marginally significant increased REMD was noted.”

May combine two claims.

Anorexia nervosa was associated with sleep discontinuity and lighter sleep, although the latter was only marginally significant.

“Anorexia nervosa was associated with sleep discontinuity and lighter sleep, although this last result was only marginally significant.”

May combine two claims.

REM pressure was increased in affective, anxiety, and autistic disorders.

“REM pressure was increased in affective, anxiety and autistic disorders.”

May combine two claims.

Reduction of sleep depth was found in major depression and PTSD (marginally significant for PTSD), but not in panic disorder.

“Within categories, reduction of sleep depth was found in major depression and PTSD (although the result was only marginally significant), but not in panic disorders.”

May combine two claims.

Shortened REML was found in patients with anxiety disorders, particularly PTSD, but no alterations in REMD and REM duration.

“Analyses for single sleep variables evidenced shortened REML in patients with anxiety disorders, and in particular PTSD, but no alterations in REMD and REM duration.”

May combine two claims.

Enhanced REM sleep pressure was found in major depression and PTSD, but not in seasonal affective and panic disorders.

“Within categories, enhanced REM sleep pressure was found in major depression and PTSD, but not in seasonal affective and panic disorders.”

May combine two claims.

Borderline personality disorder was linked with sleep discontinuity and shorter REM latency.

“Borderline personality disorder was linked with sleep discontinuity and shorter REM latency.”

May combine two claims.

Children and/or adolescents with major depression presented only marginally significant poorer sleep continuity compared to controls, but no alterations of sleep depth and REM sleep pressure.

“Children and/or adolescents with major depression, presented, in comparison with the main results, only marginally significant poorer sleep continuity compared to controls, but no alterations of sleep depth and REM sleep pressure.”

May combine two claims.

The sleep continuity result was marginally significant for eating disorder and Asperger syndrome, possibly due to small number of studies (N=5 and N=3).

“The result was marginally significant for eating disorder and Asperger syndrome, although this may be dependent on the small number of studies available for these categories (respectively N=5 and N=3).”

May combine two claims.

Within anxiety disorders, PTSD was associated with severe alterations of sleep continuity, sleep depth, and REM variables, while panic disorder was characterized by poor sleep efficiency, latency, and quantity only.

“Within anxiety disorders, PTSD was associated with severe alterations of sleep continuity, sleep depth and REM variables, while panic disorder was characterized by poor sleep efficiency, latency and quantity only.”

May combine two claims.

Children with autism presented poorer sleep continuity compared to controls, but no alterations in sleep depth and REM pressure.

“Children with autism presented poorer sleep continuity compared to controls, but no alterations in sleep depth and REM pressure.”

May combine two claims.

Sleep depth was altered in affective, anxiety, and schizophrenia disorders.

“Sleep depth was altered in affective, anxiety and schizophrenia disorders.”

May combine two claims.

In patients with depression younger than 18 years, results showed slight disruption of sleep continuity compared to controls, with no alteration in sleep depth and REM sleep pressure.

“When considering only young patients aged less than 18 years old, results showed a slight disruption of sleep continuity in those with depression compared to controls, while no alteration in sleep depth and REM sleep pressure was observed.”

May combine two claims.

Autistic disorder was correlated with both sleep discontinuity and shorter duration of REM sleep.

“autistic disorder was correlated with both sleep discontinuity and shorter duration of REM sleep.”

May combine two claims.

In elderly individuals with depression, findings indicated only a marginally significant increased REM density, and no longer altered duration of stages 1 and 2.

“Compared to main results, findings for elderly individuals with depression, indicated only a marginally significant increased REM density, and no longer altered duration of stages 1 and 2.”

May combine two claims.

Patients with schizophrenia showed poor sleep continuity and less deep sleep, but no increased REM sleep pressure compared to controls.

“Patients with schizophrenia, compared to controls, showed poor sleep continuity and less deep sleep, but no increased REM sleep pressure.”

May combine two claims.

Results suggest that sleep continuity, sleep depth, and REM sleep disturbances may be associated with borderline personality disorder.

“Results suggest that sleep continuity,sleep depth and REM sleepdisturbances may be associated with this disorder.”

May combine two claims.

REM latency was reduced in schizophrenia, but no significant result was found when considering schizophrenia without comorbidities.

“Although REM latency was found to be reduced in this group of patients, no significant result was found when considering schizophrenia in the absence of comorbidities.”

May combine two claims.

In comorbidity-excluded major depression, REM latency and REM duration showed no significance, and S1 duration was not impaired.

“Considering each variable separately, results for REM latency, and REM duration showed no significance. S1 duration was also not impaired.”

May combine two claims.

Sleep depth and REM sleep pressure disturbances were altered in a smaller number of disorders and rarely occurred in a single condition without comorbidities.

“Sleep depth and REM sleep pressure disturbances were altered in a smaller number of disorders and occurred rarely in a single condition in the absence of comorbidities.”

May combine two claims.

Only marginal significant altered sleep continuity and increased duration of stage 1 sleep were evidenced in anorexia nervosa.

“Only marginal significant altered sleep continuity and an increased duration of stage 1 sleep (i.e. light sleep) was evidenced in this condition.”

May combine two claims.

REM variables are strongly altered in major depression, the only disorder associated with alteration in all three REM variables: REM latency, REM density, and REM sleep duration.

“REM variables are strongly altered in major depression, being the only disorder associated with alteration in all three REM variables included (REM latency, REM density and REM sleep duration).”

May combine two claims.

Sleep continuity disturbances cut across current diagnostic entities and were found in all investigated disorders except ADHD and seasonal affective disorder.

“Sleep continuity disturbances cut across current diagnostic entities and were found in all investigated disorders, with the exception of ADHD and seasonal affective disorder.”

• Also stated in: § Sleep and hyperarousal as dimensions for mental health · hedged

  “Findings support the notion of transdiagnostic disruptions of sleep continuity, based on physiological (PSG) data.”

May combine two claims.

Reduction of sleep depth and increased REM sleep pressure were related to disorder comorbidity.

“reduction of sleep depth and increased REM sleep pressure were related to disorders comorbidity.”

May combine two claims.

Heterogeneity between studies was often high (I2>70) and the sources of variability directly investigated did not completely explain this high heterogeneity.

“heterogeneity between the studies was often high (I2>70) and the sources of variability that we could directly investigate did not completely explain this high heterogeneity.”

May combine two claims.

Results suggested sex differences in major depression, and different results in men samples compared to main analyses in anxiety disorders and schizophrenia.

“results suggested sex differences in major depression, as well as different results in men sample compared to main analyses in anxiety disorders and schizophrenia.”

May combine two claims.

Sleep disturbances are highly prevalent in mental disorders and have been associated with adverse cognitive, emotional, and interpersonal functioning.

“Decades of research have shown that sleep disturbances are highly prevalent in mental disorders and have been associated with adverse effects for cognitive, emotional, and interpersonal functioning”

• cites Kahn, Sheppes & Sadeh, 2013Not checked yet

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• cites Rasch & Born, 2013Not checked yet

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• cites Walker, 2009Not checked yet

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May combine two claims.

In Benca et al., the only exception was a REM density increase found exclusively in affective disorders, though analyses for this parameter were limited by insufficient studies.

“The single exception was a REM density increase found exclusively in affective disorders, although analyses for this sleep parameter were limited to only some of the disorders due to an insufficient number of studies.”

• cites Benca et al., 1992Not checked yet

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May combine two claims.

In schizophrenia, untreated patients showed sleep alterations, including increased total time awake and shorter stage 2 sleep.

“Results showed that patients presented with sleep alterations, as increased total time awake and shorter duration of stage 2 sleep during the night, even if never treated.”

• cites Chouinard, Poulin, Stip & Godbout, 2004Not checked yet

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

In Benca et al., alterations in sleep variables were not specifically linked to single disorders, questioning the specificity of any sleep variable for a particular mental disorder.

“In addition, alterations in any of the sleep variables were not specifically linked to single disorders, thus questioning the specificity of any sleep variable for a particular mental disorder.”

• cites Benca et al., 1992Not checked yet

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Classified as probably not a substantial claim.

A prior meta-analysis of 46 studies suggested major depression may involve diminished SWS duration combined with increased REM density.

“The results confirmed REM density as a possible biological marker for the disorder: more specifically, the authors suggested that major depression may be related to a combination of diminished SWS duration and increased REM density.”

• cites Pillai, Kalmbach & Ciesla, 2011Not checked yet

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May combine two claims.

PSG research in major depression is limited by conflicting findings, likely due to modest sample sizes and methodological variance.

“After these pioneer studies, PSG research in major depression continued producing a rich literature, which however is limited by many conflicting findings, probably due to modest sample sizes and methodological variance between studies”

• cites Swanson, Hoffmann & Armitage, 2010Not checked yet

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May combine two claims.

Major depression is characterized by sleep continuity alterations, shortened SWS, and increased REM sleep pressure, including longer REM duration, shortened REM latency, prolonged first REM period, and increased REM density.

“PSG research in psychopathology started in the 1960s with studies showing that major depression was characterized by alterations of sleep continuity, shortened time in SWS and increased REM sleep pressure, i.e. longer REM sleep duration, shortened REM latency, a prolongation of the first REM period, and increased REM density”

• cites Riemann et al., 1994Not checked yet

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• cites Berger & Riemann, 1993Not checked yet

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• cites Lauer et al., 1991Not checked yet

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

All schizophrenia subtypes were considered together, and no separate analysis by subtype was conducted due to insufficient studies.

“All subtypes were considered together, and no further analysis considering subtypes separately could be conducted due to a lack of a sufficient number of studies.”

May combine two claims.

All studies were estimated to address a clear focused issue and use an appropriate method.

“All studies were estimated to address a clear focused issue and use an appropriate method to answer to the research’s questions (1 & 2).”

Classified as probably not a substantial claim.

Autistic disorder and Asperger syndrome were analyzed separately.

“We considered these two disorders only separately to evaluate possible differences depending on the degree of cognitive impairment.”

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

The meta-analysis followed MOOSE guidelines.

“This meta-analysis followed MOOSE (Meta-analysis Of Observational Studies in Epidemiology) guidelines”

• cites Stroup et al., 2000Not checked yet

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Classified as probably not a substantial claim.

Diagnoses were based on DSM-IV or ICD-10.

“Diagnosis of mental disorders based on DSM-IV (APA, 1994) or ICD-10 (WHO, 2010)”

• cites APA, 1994Not checked yet

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• cites WHO, 2010Not checked yet

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

All included studies measured and scored PSG through standard sleep scoring criteria.

“All included studies measured and scored PSG through standard sleep scoring criteria.”

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

The externalizing disorders category searched exclusively for ADHD.

“For this category we searched exclusively for Attention-deficit/hyperactivity disorder (ADHD).”

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

Separate analyses for specific affective disorders were possible only for major depression and seasonal affective disorder.

“Considering our final sample of studies (see Results for details), separate analyses for specific affective disorders were possible to be conducted only for major depression and seasonal affective disorder.”

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

Global quality scores ranged between 5 and 11.

“Global quality scores ranged between 5 and 11.”

May combine two claims.

Eighty-one of 91 studies based patients' diagnoses on validated clinical interview, while 10 used validated questionnaires.

“Eighty-one studies (of 91) based patients’ diagnoses on validated clinical interview, while 10 studies used validated questionnaires.”

May combine two claims.

Only 2 studies for antisocial personality disorder were selected, so it was not evaluated in meta-analytic computations.

“However, for this last condition, only 2 studies were selected in the final database, thus it was not evaluated in meta-analytic computations.”

Classified as probably not a substantial claim.

Robust Variance Estimation was used to account for potentially statistically dependent effect sizes.

“Robust Variance Estimation (RVE, R package “robumeta”) was used to cater for potentially statistically dependent effect sizes (e.g. Hedges, Tipton, & Johnson, 2010; Tanner-Smith & Tipton, 2014).”

• cites Hedges, Tipton, & Johnson, 2010Not checked yet

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• cites Tanner-Smith & Tipton, 2014Not checked yet

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Classified as probably not a substantial claim.

Included studies required a healthy control group.

“Inclusion of a healthy control group”

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

The quality assessment used Section A of the Critical Appraisal Skills Programme Tool for Case-Control studies.

“For quality assessment, we referred to Section A of the Critical Appraisal Skills Programme Tool for Case-Control studies (Bradley & Hill, 2001).”

• cites Bradley & Hill, 2001Not checked yet

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

Sixty-five studies provided detailed information on mental disorders comorbidity.

“Sixty-five studies provided detailed information on mental disorders comorbidity.”

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

Publication bias was assessed using funnel plots and the classical safe-fail number.

“Publication bias was assessed both graphically by using funnel plots and numerically by considering the classical safe-fail number for each significant result evidenced by main analyses.”

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

Outliers were identified by standardized residuals, and studies with residuals > |3| were winsorized.

“Before performing each meta-analysis, we identified possible outliers by exploring standardized residuals. Studies with standardized residuals > |3|were winsorized, i.e. residuals were reduced to = +/−3.”

Classified as probably not a substantial claim.

Heterogeneity was tested using chi-squared tests and the I2 statistic.

“To test for heterogeneity, chi-squared tests and the I2 statistic derived from the chi-squared values were used (Borenstein, Hedges, Higgins & Rothstein, 2009).”

• cites Borenstein, Hedges, Higgins & Rothstein, 2009Not checked yet

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

Six of 91 studies followed slightly different procedural protocols for cases and controls.

“Six studies of 91 followed slightly different procedural protocols for cases and controls.”

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

Separate analyses for specific anxiety disorders were possible only for panic disorder and PTSD.

“Analyses could be computed only for panic disorder and Post-Traumatic Stress Disorder (PTSD).”

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

Meta-analyses were performed when at least 3 studies were available.

“Meta-analyses were performed when at least 3 studies were available.”

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

For RVE, degrees of freedom < 4 may indicate too few cases for reliable variance estimation.

“For this method, results with degrees of freedom < 4 could indicate too few cases for reliable variance estimation.”

• cites Hedges, Tipton, & Johnson, 2010Not checked yet

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• cites Tanner-Smith & Tipton, 2014Not checked yet

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

Possible sources of variability were controlled through subgroup analyses for sex, age, and mental disorders comorbidity.

“Possible sources of variability between the studies were controlled through meta-analytic subgroup analyses whenever a sufficient number of studies was available for the subgroup. Sex, age, and mental disorders comorbidity were considered for subgroup analysis.”

Classified as probably not a substantial claim.

The random-effects model was used because of considerable heterogeneity between studies.

“The random-effects model was used because of the considerable heterogeneity between studies (different populations, different settings, etc.).”

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

All studies in the eating disorders category focused on anorexia nervosa.

“All studies included in this category focused on anorexia nervosa.”

Classified as probably not a substantial claim.

Samples did not overlap across included studies.

“Non-overlap of samples across studies”

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

Median quality scores for most disorder categories ranged between 8 and 9.

“As shown in Table 1, median scores for most disorder categories ranged between 8 and 9.”

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

Analyses for women were possible for affective disorders, depression, and anorexia nervosa.

“Analyses for women were possible for affective disorders, depression, and anorexia nervosa.”

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

All studies excluded the first night from the analyses, except one study that tested and reported no change.

“All studies excluded the first night from the analyses as this was an exclusion criterion of our meta-analysis, apart from one study which was included as the authors specifically reported that they tested that the exclusion of the first night from the analyses did not change the results”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

Sleep may be one of the most important basic dimensions of brain function and mental health.

“Sleep, considered as a fundamental operating state of the central nervous system, and occupying up to a third of the human life span, may be one of the most important basic dimensions of brain function and mental health”

• cites Regier et al., 2012Not checked yet

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• cites Harvey et al., 2011Not checked yet

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Classified as probably not a substantial claim.

Included studies required standard sleep scoring criteria.

“Use of standard sleep scoring criteria (Iber et al., 2007; Rechtschaffen & Kales, 1968)”

• cites Iber et al., 2007Not checked yet

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• cites Rechtschaffen & Kales, 1968Not checked yet

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Classified as probably not a substantial claim.

Patients had a current episode of mental disorder at the time of PSG recordings.

“Current episode of mental disorder at the time of the PSG recordings”

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

About half of the studies (49 of 91) specified that scorers were blind to group assignment.

“About half of the studies (49 of 91) specify that scorers were blind to group assignment, while the remaining 42 either not specify this information or conducted no blind scoring.”

Classified as probably not a substantial claim.

Unpublished studies were excluded to focus on peer-reviewed methodology.

“We did not include data from unpublished studies in order to focus on those with the most rigorous research methodology subject to peer review.”

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

The first sleep laboratory night was excluded from analysis.

“Exclusion of the first sleep laboratory night (i.e. adaptation night) from the analysis”

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

A study on conduct disorder was added to the externalizing disorders category but was not considered in meta-analytic computations.

“Of note, by searching for antisocial personality disorder, we found a study evaluating polysomnography in patients with conduct disorder, which was added in the externalizing disorders category and described in this systematic review. However, this study was not considered in meta-analytic computations.”

Classified as probably not a substantial claim.

Included studies required discontinuation of psychoactive medication for at least 1 week before and during PSG.

“Discontinuation of psychoactive medication for at least 1 week before and during the PSG examination”

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

REMD could not be calculated for anxiety and autistic disorders in comorbidity-excluded analyses.

“Of note, REMD could not be calculated for anxiety and autistic disorders.”

May combine two claims.

Meta-analyses could not be performed for generalized anxiety disorder, obsessive compulsive disorder, or phobias.

“We could not perform meta-analyses for generalized anxiety disorder, obsessive compulsive disorder nor phobias.”

May combine two claims.

Increased REM activity and time are related to suicidal behaviors in individuals with depression and in psychotic patients.

“increased REM activity and time are related with suicidal behaviors in individuals with depression (Sabo, Reynolds, Kupfer & Berman, 1991) and in psychotic patients (Keshavan et al., 1994).”

• cites Sabo, Reynolds, Kupfer & Berman, 1991Not checked yet

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• cites Keshavan et al., 1994Not checked yet

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May combine two claims.

The different alterations show that PTSD and panic disorder have different sleep physiology and may be better included in different categorizations.

“These different alterations show that the two disorders present a different sleep physiology indicating that they may be better included in different categorizations.”

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

The sex difference may indicate either biological sex differences in the disorder or social differences.

“This may indicate either biological sex differences in the disorder or social differences.”

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

The current DSM-5 meta-structure separates PTSD from anxiety disorders, including panic disorder, into different chapters.

“This fits the meta-structure of the current DSM-5 (APA, 2015), that separates PTSD from anxiety disorders, including panic disorder, into different chapters (Regier et al., 2012).”

• cites APA, 2015Not checked yet

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• cites Regier et al., 2012Not checked yet

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Classified as probably not a substantial claim. May combine two claims.

Sleep architecture and REM sleep variables may be associated with neurobiological pathways underlying emotional and cognitive alterations, leading to distinct symptom associations.

“Sleep architecture and REM sleep variables may be associated with neurobiological pathways underlying different alterations of emotional and cognitive processes, thus, leading to distinct symptoms associations.”

• AssumptionRests on an assumption: Sleep-related neural pathways are closely connected and partly overlap with pathways that regulate affect, cognition, and other important brain functions.
• AssumptionRests on an assumption: Sleep architecture and REM variables are related to cognitive and emotional functioning.

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

Separate analyses for the elderly group were possible only for major depression.

“Separate analyses for the elderly group were possible to be conducted only for major depression.”

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

The extent and transdiagnostic character of sleep continuity disturbances suggest that systematic treatment of sleep continuity disturbances in clinical settings may improve the course of major mental disorders.

“The extent of sleep continuity disturbances and their transdiagnostic character foster the concept that the systematic treatment of sleep continuity disturbances in clinical settings may help to improve the course of major mental disorders.”

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

The meta-analysis assessed publication bias by visually inspecting 54 funnel plots and calculating fail-safe N for significant findings.

“Fifty-four funnel plots were visually inspected and related fail-safe classical numbers were calculated for the corresponding significant findings.”

Classified as probably not a substantial claim. May combine two claims.

ADHD being associated with hypoarousal rather than hyperarousal may explain the absence of sleep alterations.

“ADHD being a disorder associated with rather hypoarousal instead of hyperarousal, this may explain the results.”

• AssumptionRests on an assumption: ADHD is associated with hypoarousal rather than hyperarousal.

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

Comorbidity-excluded analyses could be run for affective, anxiety, autistic, schizophrenia disorders, depression, and ADHD.

“We could run these analyses for affective, anxiety, autistic, schizophrenia disorders, depression and ADHD.”

May combine two claims.

Diverse constellations of sleep architecture and REM sleep alterations may underlie specific comorbidities in psychopathology and clarify why some disorders often present together.

“diverse constellations of sleep architecture and REM sleep alterations may underline specific comorbidities in psychopathology and clarify why some disorders often present together.”

May combine two claims.

Insomnia is highly comorbid with mental and somatic disorders and increases the risk of some of them, including major depression, suicidal behaviors, and cardiovascular disease.

“insomnia, the most prevalent sleep continuity disorder, is known to be highly comorbid with mental and somatic disorders and to increase the risk of some of them, as for example major depression (Baglioni et al., 2011), suicidal behaviors (Biøngaard, Bjerkeset, Romundstad & Gunnel, 2011) and cardiovascular disease (Laugsand, Strand, Platou, Vatten & Janszky, 2013).”

• cites Baglioni et al., 2011Not checked yet

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• cites Biøngaard, Bjerkeset, Romundstad & Gunnel, 2011Not checked yet

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• cites Laugsand, Strand, Platou, Vatten & Janszky, 2013Not checked yet

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

Sleep could be investigated within the RDoC concept as a likely basic dimension in mental health.

“Our results suggest that sleep could be investigated within the RDoC concept as a likely basic dimension in mental health.”

May combine two claims.

Central cholinergic activity and supersensitivity may be excessively increased in depression and may represent a relevant neurobiological factor in affect regulation.

“central cholinergic activity and supersensitivity, responsible for the generation of rapid eye movements, may be excessively increased in depression and may represent a relevant neurobiological factor in the regulation of affect.”

• cites Palagini, Baglioni, Ciapparelli, Gemignani, & Riemann, 2013Not checked yet

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• cites Nissen et al., 2006Not checked yet

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

NIMH proposed the RDoC project to identify basic dimensions of brain/mind disorders across multiple units of analysis.

“the National Institute of Mental Health (NIMH) proposed the Research Domain Criteria (RDoC) Project (Morris, Rumsey & Cuthbert, 2014; Cuthbert & Kozak, 2013; Sanislow et al., 2010) to identify basic dimensions of brain/mind disorders to be studied across multiple units of analysis, from genes to neural circuits to behaviors.”

• cites Morris, Rumsey & Cuthbert, 2014Not checked yet

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• cites Cuthbert & Kozak, 2013Not checked yet

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• cites Sanislow et al., 2010Not checked yet

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Classified as probably not a substantial claim.

Treating sleep continuity difficulties at an early stage could interrupt the process that reduces quality of life and leads to psychopathology.

“treating sleep continuity difficulties at an early stage could interrupt the sequential process that gradually reduce the quality of life of people with insomnia and ends in the development of symptoms of psychopathology.”

• AssumptionRests on an assumption: There is a longitudinal association between insomnia and depression and mental disorders in general.

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

DSM-5 combines categorical and dimensional measurement.

“DSM-5 (American Psychiatric Association, APA, 2013) follows a new approach, combining categorical and dimensional measurement (Kupfer et al., 2013; Regier et al., 2012).”

• cites Kupfer et al., 2013Not checked yet

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• cites Regier et al., 2012Not checked yet

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

Subgroup analyses suggest that major depression may be less severe in developmental age, and clinical interventions may be more effective in early age compared to adult groups.

“Subgroup analyses focusing on pediatric patients with major depression suggest that the disorder may be less severe in the developmental age, thus it could be possible that clinical interventions may be more effective in early age compared to adult groups.”

• AssumptionRests on an assumption: Sleep is related to developmental outcomes, including brain maturation, learning, memory, temperament, emotional regulation, relational skills, and physical wellbeing.
• AssumptionRests on an assumption: Interventions in early age may have a large impact across the lifespan.

Classified as probably not a substantial claim.

Analyses could not be run for conditions such as bipolar disorder or generalized anxiety disorder.

“We could not run analyses for conditions such as bipolar disorder or generalized anxiety disorder.”

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

The available data did not allow consideration of sleep within the context of circadian organization of the sleep-wake cycle.

“The available data did not allow consideration of sleep within the context of circadian organization of the sleep-wake cycle.”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

This absence may have obscured important windows into mental disorders pathophysiology.

“This may have obscured important windows into mental disorders pathophysiology.”

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

Only a few analyses could be conducted for sex subgroups.

“only a few analyses could be conducted for sex subgroups.”

May combine two claims.

PSG research is still largely focused on major depression, while other mental disorders have been rarely evaluated.

“PSG research is still largely focusing on major depression, while other mental disorders have been rarely evaluated.”

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

Only few analyses could be run for REM density.

“we could run only few analyses for REM density”

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

This could not be tested in the analyses due to insufficient data.

“This could however not be tested in our analyses due to insufficient data.”

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

Some sleep variables have been less frequently considered than others.

“Some sleep variables have been less frequently considered than others.”

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

Mental disorders may differ for circadian timing of major sleep periods and naps.

“It could be possible that mental disorders differ for circadian timing of major sleep periods and naps, as we know that this explains for example, at least in part, age changes (Cajochen, Münch, Knoblauch, Blatter & Wirz-Justice, 2006).”

• cites Cajochen, Münch, Knoblauch, Blatter & Wirz-Justice, 2006Not checked yet

  Not checked in the free run.

May combine two claims.

Comorbidity with depression was likely frequent in most PTSD studies and could have influenced results.

“it is likely that comorbidity with depression was frequent in most PTSD studies and could have influenced results.”