Longer Time to Antipsychotic Treatment Discontinuation for Any Cause Is Associated With Better Functional Outcomes for Patients With Schizophrenia, Schizophreniform Disorder, or Schizoaffective Disorder

Objective: Time to all-cause treatment discontinuation is considered a composite proxy measure of treatment efficacy, safety, and tolerability. Longer time to discontinuation of antipsychotic medication for any cause has been shown to be associated with greater symptom improvements in the treatment of schizophrenia. This study examines whether longer time to all-cause medication discontinuation is also linked to better functional outcomes.

Method: Using pooled data from 4 randomized, double-blind antipsychotic trials of 24- to 28-weeks' duration, this study examined the association between time to all-cause treatment discontinuation and functional outcomes, as assessed by a disease-specific, clinician-rated measure (Quality of Life Scale [QLS]) and a generic, patient-reported measure (Medical Outcomes Study Short Form 36 [SF-36]). Patients in these trials had a DSM-IV diagnosis of schizophrenia, schizophreniform disorder, or schizoaffective disorder. This post hoc analysis used Pearson partial correlations to assess relationships between time to treatment discontinuation and changes in functional scores, adjusting for baseline scores. Repeated measures analyses were also conducted to compare postbaseline functional outcome change over time between completers and noncompleters.

Results: Longer time to all-cause treatment discontinuation was found to be significantly associated with greater improvements in all assessed functional domains (p < .05). Patients who completed their respective trials (46.8%, 761/1627) experienced significantly greater improvement in functional outcome measures (in 4 QLS domains and SF-36 mental health componentsummary score; all, p < .001) compared to patients who discontinued for any cause. In addition, greater symptom improvement was significantly associated with greater functional improvements in assessed domains.

Conclusions: Findings from this post hoc analysis illustrate the importance of longer treatment duration with antipsychotics for improving functional outcomes in the treatment of patients with schizophrenia.

J Clin Psychiatry 2007;68(8):1163-1171