Effects of the number of hospitalizations on cognitive function in Japanese patients with stable schizophrenia

Abstract Background The present study aimed to determine whether the number of hospitalizations in schizophrenia patients is associated with reduced cognitive performance, which may in turn imply that recurrences indirectly lead to a worsening in the disorder’s progression. Methods Cognitive performance in stable schizophrenia patients was assessed using the Brief Assessment of Cognition in Schizophrenia, Japanese-language version, on 30 patients who had not experienced any hospitalizations (G0), 57 patients who had experienced only one hospitalization (G1), 47 patients with two hospitalizations (G2), and 59 patients with three or more hospitalizations (G3). Results Significant differences in motor function and attention and processing speed were found between patients with G0 and those with G1. Significant differences in working memory and verbal fluency were found between patients with G1 and those with G2. Patients with G3 performed even more poorly in comparison with those with G1, showing deficits in verbal memory, working memory, executive function, and composite score. The patients with G3 displayed a greater range of impairment and demonstrated deficits in executive function compared with patients with G2. Finally, G2 and G3 performed more poorly than G0, with deficits in the various cognitive areas. Conclusion The number of hospitalizations predicted cognitive performance, which suggests that relapse or recurrence may have a long-term neuropsychological impact. Prospective follow-up studies must be completed to explore this effect further because better treatment adherence may have a protective effect on neurocognitive function.