Cognitive Impairment in Schizophrenia Is the Core of the Disorder

“Of the many clinical features of schizophrenia, disturbances in certain cognitive processes, such as impairments in attention, memory and executive functions (that is, the ability to plan, initiate and regulate goal-directed behaviour), might represent the core features of the illnes”

“Although positive symptoms are the most noticeable manifestations of this disease, cognitive deficits are perhaps the most distinctiv”

“The intermediate (schizophrenia) phenotypes, of moderately diminished premorbid IQ and related cognitive measures (Elvevag and Goldberg 2000; Weickert et al. 2000), may be an interesting connection between the function of the DPC in synaptic transmission and the observed association between…”

“Cognitive symptoms include deficits in multiple domains such as executive functioning, attention, and working memory (Elvevag and Goldberg, 2000; Piskulic et al., 2007).”

“…that cognitive dysfunction is the core deficit in schizophrenia consistent with the original terminology for this disorder, dementia praecox (Kraepelin 1909; Goldman-Rakic 1991, 1994; Andreasen 1997; Green 1997; Weinberger and Gallhofer 1997; Meltzer et al. 1999; Elevag and Goldberg 2000).”

“The existence of a group of neuropsychologically normal persons with schizophrenia is inconsistent with the idea that NP impairment is a core feature of schizophrenia.(7) Thus, the existence of such a subgroup could have important implications for efforts to understand not only the neuropathology of this disorder but…”

“Instead, cognitive dysfunction is becoming regarded as the core feature of schizophrenia (Elvevag and Goldberg, 2000) and many lines of evidence support this hypothesis.”

“Cognitive deficits, including working memory impairment, appear to be the core of the dysfunction in schizophrenia (Elvevag and Goldberg, 2000; Harvey et al., 2004; Castner et al., 2004), especially with respect to central executive processing, and may further reflect forms of attentional dysfunction, such as sustaine…”

“In fact, schizophrenia patients, who show clear cognitive impairment (Elvevåq and Goldberg, 2000; Harvey et al., 2001), display abnormal cortical oscillatory activity in the slow and gamma frequency bands (Hoffmann et al.”

“Evidence supporting this idea includes that IL neurons show increased spiking during the recall of extinction learning and electrical stimulation of the IL generates extinction-like effects (Milad and Quirk, 2002), while the disruption of IL targets in the amygdala prevents extinction recall (Falls et al., 1992; Likht…”

“Cognitive deficits Patients with schizophrenia show a broad spectrum of neurocognitive deficits (reviews, Elvevag and Goldberg, 2000; Kuperberg and Heckers, 2000; Sharma and Antonova, 2003).”

“Although psychosis is usually the most striking clinical aspect of schizophrenia, disturbances in certain cognitive processes, such as attention, certain types of memory, and executive functions, are considered to be the core features of the illness.(4) Such cognitive disturbances (1) can be present for years before t…”

“…prenatal influenza infection to cognitive functions known to be disrupted in schizophrenia (Table 1) is therefore clearly warranted because cognitive deficits are recognized to be an essential component in the psychopathology of this disorder (Goldman-Rakic, 1991, 1994; Elvevag and Goldberg, 2000).”

“, 1997; Drevets, 2001) and cognitive deficits in schizophrenia patients are mediated by derangements in brain circuits involving the prefrontal cortex (Bertolino et al., 2000; Elvevag and Goldberg, 2000).”

“One of the more studied and reproducible cognitive impairments in schizophrenia is an impairment in working memory (Elvevag and Goldberg 2000; Goldman-Rakic and Selemon 1997).”

“In this regard, it has been argued that among the clinical manifestations of schizophrenia, the deficits in cognitive abilities are the core features of the illness (Elvevag and Goldberg, 2000).”

“to be the primary and persistent manifestation in patients with schizophrenia (Elvevag and Goldberg, 2000; Keefe et al., 2006; Andreasen, 1999).”

“Hydrocephalus (7), increased ventricular size (8), and cognitive impairment (9) have also been noted in some persons with schizophrenia and other forms of psychosis.”

“Although positive symptoms are most prominent, cognitive impairments are considered to be the core feature of the illness (Elvevag and Goldberg, 2000; Gold, 2004).”

“Working memory impairment: a core feature of schizophrenia Of the multiple clinical signs and symptoms of schizophrenia ( Box 1 ), impairments in cognition are now considered to be the core features of the disorde”

“Various observations (for review see ref 2) have led to the hypothesis that compromised cognitive functioning is a core feature of schizophrenia and not an artifact of other symptoms, treatment for the illness, or aspects of the course of the illness.(3,4) It has further been proposed that the well-known diversity of…”

“Cognitive deficits, among the core clinical features of schizophrenia (1), appear to reflect dysfunction of a number of cortical regions.”

“…cognitive impairments may primarily affect domains of executive functions, sustained attention andworkingmemory (Marsland et al., 2006; Holden et al., 2008; Cohen et al., 2011), all ofwhich have been implicated in schizophrenia (Elvevåg & Goldberg, 2000; Bowie & Harvey, 2006; Tandon et al., 2009).”

“Although psychosis is frequently the most striking clinical feature of schizophrenia, disturbances in critical cognitive processes are now regarded as a core feature of the illness (Elvev g and Goldberg 2000).”

“…disorder (Perlstein et al, 2001; Stirling et al, 2006), and functional outcomes in schizophrenia (Kurtz et al, 2005; Liddle, 2000), in line with the suggestion that frontal lobe dysfunction is crucially important in schizophrenic psychopathology (Elvevag and Goldberg, 2000; Weinberger et al, 1994).”

“…impairments in schizophrenia-spectrum disorders as well as recent paucity of research into the relationship between neurocognitive functioning and adherence behaviour (Elvevag and Goldberg, 2000; Keefe and Fenton, 2007), further exploration is necessary to reach more meaningful conclusions.”

“Finally, long-term users of cannabis exhibit deficits in cognitive functions, such as working memory,(13) that are impaired in schizophrenia.(14) Working memory processes depend on the circuitry of the dorsolateral prefrontal cortex (DLPFC), andalterations in thisbrain region appear to contribute to working memory imp…”

“Schizophrenia is consistently associated with disturbances in cortical information processing, working mem- ory and executive functions (Elvevag and Goldberg, 2000; Goldman-Rakic, 1994).”

“In that respect, the analysis presented here sheds light on how impaired miRNA formation alters the structure and function of neural circuits thought to underlie susceptibility to SCZ and other psychiatric disorders.”

“While positive and negative symptoms have long been considered the hallmark features of schizophrenia, recent clinical studies have highlighted cognitive dysfunction as a third major diagnostic category which is increasingly considered to be the core deficit of the disorder (Goldman-Rakic 1991, 1994; Andreasen 1997; G…”

“Learning and working memory are behavioural domains of therapeutic interest for schizophrenia, which is marked by cognitive deficits (Elvevag & Goldberg, 2000).”

“…in several frequency bands have been observed in the PFC of psychiatric patients (Başar and Güntekin, 2008), notably patients with schizophrenia (Spencer et al., 2003; Cho et al., 2006; Uhlhaas et al., 2008), who show clear cognitive impairment (Elvevåg and Goldberg, 2000; Harvey et al., 2001).”

“An impairment in cognition is a hallmark symptom experienced by individuals with schizophrenia, and has been postulated to be a core aspect of the disorder (11).”

“This disorder seriously damages thoughts, expression of emotions, and also individuals’ perception of reality (Elvevag and Goldberg, 2000).”

“This is accompanied by more specific cognitive impairments such as abnormalities in perception, inferential thinking, volition, linguistic fluency, attention, executive functions (planning), and working memory [295, 296].”

“Each of these processes also is disrupted in patients with psychiatric illness (Weinberger et al., 1986; Elvevag and Goldberg, 2000).”

“Second, there is evidence for relatively specific working memory and attention deficits among schizophrenics and schizotypes (Elvevag & Goldberg, 2000; Kenny et al., 1999; Kirrane & Siever, 2000).”

“…the symptomatology of SZ as structured in terms of positive symptoms, such as psychosis; negative symptoms, such as anhedonia, which refers to the inability to experience pleasure from activities usually found enjoyable, such as social interaction; and cognitive deficits (Elvevåg & Goldberg, 2000).”

“Impairments in these domains have been well documented in studies of schizophrenia (2, 39), including in first-episode patients (25, 40) as well as nonaffected first-degree relatives (7, 41).”

“(Elvevag and Goldberg, 2000).”

“Cognitive deficits are a core feature of schizophrenia (51).”

“Neurocognitive deficits are also common in schizophrenia spectrum disorders, and are thought to be more closely linked to the biological underpinnings of the disorder than clinical symptoms [2].”

“We examined the relationships between insight, clinical measures (positive, negative symptoms, general psychopathology, and Clinical Global Impression), premorbid adjustment, age of onset, illness duration, and cognitive performance on a variety of tasks tapping into attention, memory, and executive functions—known to…”

“…depression (Arango et al., 2002; Delgado, 2000) and anxiety disorders (Deakin, 1998; Stein and Stahl, 2000) and these conditions often present with cognitive impairments that may be related to serotonergic dysfunction (Bearden et al., 2001; Elvevag and Goldberg, 2000; Porter et al., 2003a).”

“Current antipsychotics show limited effectiveness in targeting these symptoms (Elvevag and Goldberg, 2000; Hanson et al., 2010).”

“Schizophrenia is a mental disorder that is characterized by a variety of symptoms, with cognitive deficits being recognized as both the core and enduring features of this illness [197].”

“Several important aspects of the experimental and classification design mitigate the limitations of using light microscopy to identify synapses: (1) the use of two presynaptic markers (PV and GAD65) and a postsynaptic marker (GABAA α1 subunit), (2) strict object mask size requirements that were restricted to a biologi…”

“Finally, long termusers of cannabis show deficits in cognitive functions, such as working memory (Solowij et al., 2002), that are also impaired in schizophrenia (Elvevag and Goldberg, 2000).”

“Schizophrenic patients may exhibit deficits in attention, motivation, and memory, thereby affecting their ability to benefit from a weight management program.(17) However, some reports have indicated relatively high efficacy with regard to weight control in patients with From the last-observation-carried-forward data…”

“br long-term outcome (Elvevag and Goldberg, 2000; Lesh et al., 2011).”

“Because patients with these disorders also show both cognitive deficits associated with PFC function (Elvevåg and Goldberg, 2000; Lewis et al., 2003) and altered prefrontal dopamine neurotransmission (Knable and Weinberger, 1997; Kulisevsky, 2000; Abi-Dargham et al., 2002), it seems likely that…”

“On the other hand it is capable of providing a theoretical ground for a cognitive dimension of schizophrenia (Elvevåg and Goldberg, 2000).”

“Cognitive impairments, such as alterations in working memory and executive function (Carter et al. 2008), are a core feature of schizophrenia (Elvevag & Goldberg, 2000) and the best predictor of functional outcome (Green et al. 2000).”

“Furthermore, learning and memory impairments are found in psychiatric and neurological disorders associated with abnormalities in PFC transmission such as schizophrenia (Park and Holzman, 1992; Elvevåq and Goldberg, 2000).”

“Whilst dysfunction has been reported across several cognitive domains (Elvevag and Goldberg 2000), impairments in executive function have long been considered to be the core feature of schizophrenic illness (Goldberg et al. 1988; Sullivan et al. 1994).”

“Cognitive impairment is recognized as a core deficit of schizophrenia [1] and is highly correlated with functional impairment [2–4].”

“Impairments in working memory [81, 82], PPI [83], and social withdrawal [84] are prominent features of schizophrenia symptomatology.”

“…cognitive symptoms in psychiatric disorders, such as schizophrenia, has been emphasized given the early emergence of these symptoms, their ubiquitous presentation, and their predictive value for patient outcomes (Elvevag and Goldberg, 2000; Keefe and Fenton, 2007; Lewis and Gonzalez-Burgos, 2008).”

“6.4 Cognitive training Cognitive impairment is a core feature of schizophrenia and is frequently associated with poor long-term functional outcome (Elvevag and Goldberg, 2000; Lesh et al., 2011).”