Cognition in Schizophrenia: A Systematic Review of Wechsler Adult Intelligence Scale Studies

Objective: To critically analyze the evidence regarding changes in verbal and performance intelligence quotient (IQ) in patients with schizophrenia.

Data Sources: An English-language-only search was conducted in the PubMed, Cochrane Library, and LILACS databases for articles with study objectives that included Wechsler Adult Intelligence Scale (WAIS) assessment of cognitive functions in patients with schizophrenia. Descriptors were defined based on Medical Subject Headings, where associations of psychotic disorders related to the schizophrenia spectrum were suggested, as well as the "Wechsler Scales" descriptor. The search was conducted in November 2022 with no restriction on the date of publication to select studies that used any of the WAIS editions.

Study Selection: Articles that met the inclusion criteria were selected after title and summary identification and full-text review.

Results: A total of 28 articles were identified. All studies presented total IQ scores, but only 20 showed results for verbal IQ (n = 20) or performance IQ (n = 19). Analyzed data indicated patients had average performance on verbal comprehension features but low average performance on perceptual reasoning, working memory, and processing speed indices.

Conclusions: Executive function deficits were found in the analyzed studies, which reflect difficulties in planning and impulse control-characteristics present in the diagnosis of schizophrenia. The identification of this neuropsychological functioning contributes to the understanding of the cognitive dynamics found in schizophrenia and may help in early diagnosis, reinforcing the hypothesis that cognitive performance may be one of the indicators of psychopathologic expression.

Prim Care Companion CNS Disord 2023;25(5):22r03456.

Author affiliations are listed at the end of this article.