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

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.

To compare memory impairment in patients with SZ, BD with psychosis, and BD without psychosis.

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).

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.

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.