Memory Impairment in Patients With Schizophrenia and Bipolar Disorder With and Without Psychosis: A Comparative Study

Background: Cognitive impairment is a common symptom in both Schizophrenia (SZ) and Bipolar Disorder (BD), and studies have demonstrated memory impairment in patients with these disorders. Objectives: To compare memory impairment in patients with SZ, BD with psychosis, and BD without psychosis. Materials & Methods: This study was a cross-sectional study conducted on 42 patients referred to Shafa Hospital in Rasht, Iran. Patients were examined in 3 groups of 14 people each (SZ, BD with psychosis, and BD without psychosis). The study tools included a demographic information questionnaire, a Brief Psychiatric Rating Scale (BPRS), and Wechsler’s Memory Scale (WMS) for adults. The obtained data were analyzed by SPSS version 21 using the 1 way analysis of variance (ANOVA). Results: The mean BPRS scores in patients with SZ (47.28) was higher than that in BD with psychosis (43.93) and BD without psychosis (23.14). ANOVA results showed a significant difference between patients with SZ and BD without psychosis (P=0.001), as well as BD with psychosis and BD without psychosis (P=0.001). Also, there was a statistically significant difference in the mean WMS scores between patients with SZ (62.07) and BD with psychosis (76.57) (P=0.009) and between SZ and BD without psychosis (73.5) (P=0.047). BPRS and WMS scores in SZ and BD without psychosis patients had a negative correlation. Conclusion: The results showed that SZ is associated with weaker memory than BD, and a history of psychosis does not have a significant effect on memory function in patients with BD.

Keywords:

Cognition , Memory , Schizophrenia , Bipolar disorder , Psychotic disorders