Psychopathology and Wisconsin Card Sorting Test performance in male schizophrenic patients: influence of dual diagnosis.

BACKGROUND

Different neuropsychological studies have shown schizophrenic patients to have executive function deficits, as illustrated by their performance in neuropsychological tasks such as the Wisconsin Card Sorting Test (WCST); certain studies have described a relationship between these deficits and negative symptoms. Schizophrenic patients also exhibit a high lifetime prevalence (40-50%) of comorbid substance use disorders (SUDs). However, little attention has been paid to this comorbidity (dual diagnosis) in studies associating executive functions and negative symptoms.

SAMPLING AND METHODS

Our objective is to investigate the relationship between performance in the WCST and psychopathology as measured by the Positive and Negative Syndrome Scale (PANSS) in a sample of 65 male schizophrenic patients with a history of SUDs (Sch SUD+) and in a sample of 48 male schizophrenic patients without such history (Sch SUD-).

RESULTS

In the Sch SUD- group, patients who completed 4 or more categories in the WCST ('good performers') obtained a mean score of 21.2 +/- 8.8 on the negative subscale of the PANSS, compared with a mean score of 27.8 +/- 8.6 in those who completed 3 or less ('poor performers'); these differences were statistically significant (p = 0.015). In the Sch SUD+ group, however, no association was found between WCST performance and the PANSS negative subscale score.

CONCLUSIONS

The presence of a history of comorbid SUDs should be taken into consideration in studies investigating executive functions and negative symptoms in schizophrenia.