Longitudinal Studies of Cognition in First Episode Psychosis: A Systematic Review of the Literature

Abstract

Although cognitive deficits are recognized as a core feature in schizophrenia, their evolution over the course of the illness is still debated. Longitudinal studies of cognition in patients after a first episode of psychosis (FEP) provide extremely useful information, in that they include an adequate and realistic baseline measure of cognitive performance, while at the same time minimizing the effect of confounding variables associated with chronicity. The aim of this systematic review was to summarize findings of studies assessing the longitudinal course of neuropsychological deficits in patients with FEP for durations of at least one year. Overall, the neuropsychological deficits that are present following a first episode of psychosis appeared to remain stable over time for periods of up to ten years, the only possible exception being verbal memory deficits, where there is some evidence of further deterioration over the long term. However, further studies are needed to confirm this conclusion, especially in the (somewhat inconsistently defined) domain of executive function. Improvements in psychopathology appear to positively influence the course of cognitive deficits, although the effects of antipsychotic medication are not as clear.

Cognitive course in first-episode psychosis and clinical correlates: A 4 year longitudinal study using the MATRICS Consensus Cognitive Battery

“…The comprehensive deficits in cognitive capacity in individuals with psychosis are consistent with the literature, specifically a reduced improvement in processing speed and verbal learning over time relative to other cognitive domains has previously been reported (Juuhl-Langseth et al, 2014;Rodríguez-Sánchez et al, 2013;Bozikas and Andreou, 2011), although not uniformly (Leeson et al, 2009). Stability in the remaining cognitive deficits has also been identified in measures of attention Ayesa-Arriola et al, 2013) social cognition (Horan et al, 2012) working memory de Mello Ayres et al, 2010) reasoning and problem solving (Juuhl-Langseth et al, 2014) and visual learning .…”

“…In general, it has been shown that the majority of cognitive deficits remain stable following an initial psychotic episode (Bozikas and Andreou, 2011;Bora and Murray, 2013), although there is variability throughout the literature. For example, verbal learning has variously been reported to either remain stable over 3 years , to deteriorate over 10 years and 13 years (Bozikas andAndreou, 2011, Øie et al, 2010); or to improve over 6 months and 2 years (Jahshan et al, 2010;Barder et al, 2013).…”

“…For example, verbal learning has variously been reported to either remain stable over 3 years , to deteriorate over 10 years and 13 years (Bozikas andAndreou, 2011, Øie et al, 2010); or to improve over 6 months and 2 years (Jahshan et al, 2010;Barder et al, 2013). A table of recent longitudinal studies, consisting of studies additional to the meta-analysis by Bora and Murray (2013) is provided in Table 1.…”

Preserved, deteriorated, and premorbidly impaired patterns of intellectual ability in schizophrenia.

“…Neurocognitive deficits are considered the most stable aspect of schizophrenia, with test-retest coefficients ranging from 0.70 to 0.85 (Albus et al, 2002;Bozikas & Andreou, 2011;Censits, Ragland, Gur, & Gur, 1997;Hoff et al, 1999). The stability of these deficits has been established in numerous studies.…”

Event-related potentials and changes of brain rhythm oscillations during working memory activation in patients with first-episode psychosis

“…2 They start as early as the prodromal state 3 and may remain relatively stable over time after the first episode of psychosis. 4 Despite substantial research efforts, the origin of working memory disturbances in patients with schizophrenia remains obscure. In fact, these disturbances cannot be fully explained by clinical factors, such as duration of illness, antipsychotic medication or symptom profile.…”