Cognitive functions in methamphetamine induced psychosis compared to schizophrenia and normal subjects

OBJECTIVE The purpose of this research was to study the cognitive functions in patients with methamphetamine-induced psychosis (MIP) in comparison with schizophrenia patients and normal subjects. METHOD This was a cross-sectional study, 30 patients with MIP, 30 patients with schizophrenia and 30 normal individuals were selected via convenient sampling and were matched on age, sex and education. Wisconsin Cards Sorting, Stroop, Visual Search and Attention and Wechsler Memory Tests were used to assess the subjects. RESULTS The study showed that patients with MIP and schizophrenia have more deficits in executive functions, selective attention, sustained attention and memory than normal subjects. There were no significant differences in cognitive functions between patients with MIP and schizophrenia except for visual search and attention that showed more impairment in patients with schizophrenia. CONCLUSION Although, cognitive dysfunctions of patients with MIP are mostly similar to patients with schizophrenia, some differences seem to exist, especially in those functions that are not primarily dependent on frontal lobe.