Cognitive neuropsychological functioning was examined in 54 adult Māori diagnosed with schizophrenia and 56 controls, matched on sociodemographic variables, handedness and premorbid cognitive ability. The study also analysed associations between cognition, medication and symptoms of psychosis in the schizophrenia group. In neuropsychological testing of attention, executive ability, motor, premorbid ability, verbal/non-verbal memory and verbal fluency (English/Māori versions), performance was significantly poorer in the schizophrenia group versus the control group on all tests, except the test of attention. Effect sizes were moderate to large: 0.78 for motor function; 1.3 for executive ability, verbal fluency and visual memory; 1.6 for verbal learning and 1.8 for verbal memory. These differences persisted in analyses that adjusted for multiple comparisons and covariates. A higher dose of antipsychotic medication and a higher anticholinergic load were associated with greater verbal memory impairment (r = −0.38 and r = −0.38, respectively). A longer duration of illness was associated with greater impairment of verbal memory (rho = −0.48), verbal learning (rho = −0.41) and visual memory (rho = −0.44).
