Long-Term Changes in Self-Report Auditory Verbal Hallucinations in Patients with Schizophrenia Using Clozapine

This study explored long-term changes in self-report auditory verbal hallucinations (AVHs) among patients with schizophrenia taking clozapine. Forty-four patients who were evaluated more than twice and were above the mild severity category on the Hamilton Program for Schizophrenia Voices Questionnaire (HPSVQ) were enrolled. The mean observation period was 492.5±350.1 days (median, 452 days). The mean total, physical, and emotional factor scores on the HPSVQ were significantly reduced from baseline to the final observations except for one item "interference with life," which was not significantly reduced. Regarding the time-dependent longitudinal changes modeled using linear mixed-effect regression, the total and physical factor scores showed significant changes during the first year, but the emotional factor score did not satisfy a more stringent level of significance. Female gender was negatively associated with the reduction in total and physical factor scores. The duration of treatment with clozapine also had a negative relationship with the reductions in all three scores.