Time to discontinuation of first- and second-generation antipsychotic medications in the treatment of schizophrenia.

BACKGROUND

Continuous adherence to antipsychotic treatment is critical for individuals with schizophrenia to benefit optimally, yet studies have shown rates of antipsychotic discontinuation to be high with few differences across medications. We investigated discontinuation of selected first- and second-generation antipsychotics among individuals with schizophrenia receiving usual care in a VA healthcare network in the U.S. mid-Atlantic region.

METHODS

We identified 2138 VA patients with schizophrenia who initiated antipsychotic treatment with one of five non-clozapine second-generation antipsychotics or either of the two most commonly prescribed first-generation agents between 1/2004 and 9/2006. The dependent variable was duration of continuous antipsychotic possession from the index prescription until the first gap of more than 45 days between prescriptions. We used the Cox proportional hazards model to compare the hazard of discontinuation among the seven antipsychotics controlling for patient demographic and clinical characteristics. The reference group was olanzapine.

RESULTS

The majority of patients (84%) discontinued their index antipsychotic during the follow-up period (up to 33 months). In multivariable analysis, only risperidone had a significantly greater hazard of discontinuation compared to olanzapine (Adjusted hazard ratio=1.15, 95% CI: 1.02-1.30, p=.025). Younger age, non-white race, homelessness, substance use disorder, recent inpatient mental health hospitalization, and prescription of another antipsychotic were also associated with earlier discontinuation.

CONCLUSIONS

Examination of a usual care sample of individuals with schizophrenia revealed short durations of antipsychotic use, with only risperidone having a shorter time to discontinuation than olanzapine. These findings demonstrate that current antipsychotic agents have limited overall acceptability by patients in usual care.