Neuropsychological functioning in subtypes of schizophrenia and mood disorders
The study investigated differences in patterns of neuropsychological functioning among 265 psychiatric inpatients whose DSM-IV diagnoses included paranoid schizophrenia (n = 50), nonparanoid schizophrenia (n = 57), schizoaffective disorder (n = 55), major depressive disorder (n = 49), and bipolar disorder (n = 54). Subjects were drawn from a larger population of inpatients with chronic psychotic symptoms and a high prevalence of substance abuse. Potential confounds, including medication effects, substance abuse, length of hospitalization, and the stability of neuropsychological functioning in severe and persistent psychiatric disorders were considered. Measures included the Mattis Dementia Rating Scale (Mattis, 1973), the Wechsler Adult Intelligence Scale-Revised (Wechsler, 1981), and the Bender Gestalt Test (Bender, 1938). A major finding was the consistently superior performance of subjects with paranoid schizophrenia over subjects with nonparanoid schizophrenia. This pattern of robust differences in general performance, as well as on measures of memory, executive functioning, and school learning lends support to the diagnostic validity of these two subtypes of schizophrenia, with implications for both research and clinical practice. No significant differences in general neuropsychological functioning or on specific tests of attention, memory, or psychomotor speed were found between subjects with major depressive disorder and bipolar disorder. Comparisons of subjects with schizophrenia to subjects with mood disorders yielded mixed results. Patients with schizophrenia displayed significantly poorer memory functioning, and obtained significantly lower scores on some, but not all measures of executive function. The results failed to support an association between greater length of hospitalization and neuropsychological impairment. The study design included subjects' histories of substance abuse and dependence, but incorporation of past abuse or non-abuse did not impact the results as reported. Likewise, the study controlled for levels of antipsychotic and anticholinergic medication, but there were no effects on the pattern of findings.
Badgett, Scott Allen, "Neuropsychological functioning in subtypes of schizophrenia and mood disorders" (1999). ETD Collection for Fordham University. AAI9926915.