Correlating cognitive functions to symptom domains and insight in Egyptian patients with schizophrenia

Cognitive impairment is one of the fundamental features among patients with schizophrenia. The relationship between schizophrenia symptoms, insight and cognitive domains remains controversial. We aimed to study these relations in a sample of Egyptian patients with schizophrenia.

A total of 109 patients with schizophrenia were assessed using Structured Clinical Interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders (4th ed.)) Axis I diagnosis (SCID-I), Positive and Negative Syndrome Scale (PANSS) and Scale to Assess Unawareness of Medical Disorder (SUMD). Cognitive functions were assessed using the Wechsler Adult Intelligence Scale (WAIS), the Wisconsin Card Sorting Test (WCST) and the Wechsler Memory Scale (WMS). The cognitive functions would be distributed to cover six cognitive domains: attention/vigilance speed of processing, verbal learning, visual learning, working memory and reasoning/problem solving.

There was a significant correlation between all cognitive domains (except attention) and PANSS subscales. PANSS negative and general psychopathology subscales were significantly correlated with five cognitive domains: speed of processing, verbal learning, visual learning, working memory and reasoning/problem solving. PANSS negative subscale was significantly correlated with verbal learning (verbal paired association 1) and visual learning (visual paired association 1). There was a significant correlation between all cognitive domains and SUMD, except verbal and visual learning domains assessed by verbal and visual paired association 1 subtests, as well as attention assessed by failure to maintain set subtest. Only visual learning (trials administered), working memory (percentage error), and processing speed (perseverative responses, and trials to complete first category) were significantly negatively correlated to SUMD.

Cognitive impairment in patients with schizophrenia is most likely to underlie negative symptoms, general psychopathology symptoms and poor insight, suggesting that treatment strategies minimizing these symptoms would improve cognitive impairment.