Relationship between clinical improvement and functional gains with clozapine in schizophrenia

Impairment in psychosocial functioning is a key feature in schizophrenia, but few studies have examined the relationship between improvements in symptoms and functioning. We examined the relationship between change in symptoms and change in functioning in a group of patients with treatment-resistant schizophrenia after 6 and 12 weeks of clozapine treatment. Participants were assessed prior to clozapine and again at 6 and 12-week on the 18-item Brief Psychiatric Rating Scale (BPRS) and the Social and Occupational Functioning Scale (SOFAS). Change scores in BPRS and SOFAS at 6 and 12-week post-clozapine were calculated and the direct relationship was assessed via regression models. Forty-three participants were included in this study; age of sample was 42.1±12.7 years, with 31 (72.1%) male participants. At baseline, the mean BPRS total and SOFAS scores were 46.98±12.86 and 33.07±10.79, respectively. There were significant improvements in BPRS total and SOFAS scores at 6 weeks, but no significant differences between 6 and 12-week assessments. There was no significant change in negative symptoms at both follow-up assessments. At 6-week, change in symptoms was not correlated with change in functioning and while the relationship between change in symptoms and functioning was stronger at 12 weeks, none of the BPRS factors emerged as a significant predictor. The present study found that lower baseline SOFAS score was the most robust predictor for improvements in SOFAS at 6 and 12-weeks. There appears to be a "ceiling" for functional improvements on clozapine, but follow-up studies are needed to examine functional gains beyond 12 weeks.