Electronically monitored adherence in outpatients with schizophrenia or schizoaffective disorder: A comparison of first- vs. second-generation antipsychotics

Objective: To examine the effect of first- vs. second-generation antipsychotics on electronically monitored adherence in outpatients with schizophrenia or schizoaffective disorder. Method: The sample consisted of 61 outpatients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder who took either a first-generation (N = 25) or second-generation (N = 36) oral antipsychotic during study participation. Treatment group designation (first-vs. second-generation antipsychotic) was based on the particular antipsychotic medication the patient was receiving as part of routine care at study entry (i.e., non-random assignment). Adherence to prescribed antipsychotic medication was assessed monthly over a 6-month study period using electronic monitoring (EM) of medication bottle opening. Various participant characteristics were collected at baseline to test for group differences and for potential associations with prospectively measured adherence. The primary data analysis was a mixed-model analysis of repeated measures. Results: The analysis of EM adherence revealed no significant difference between those taking first-generation (6-month adjusted mean adherence = 64.35%) and second-generation antipsychotics (6-month adjusted mean adherence = 69.17%; Group effect, p = .29) and no significant Group X Period interaction (p = .13). Conclusion: There was no statistical difference in EM adherence, over a 6-month period, between patients taking first- and second-generation antipsychotics. However, since the patients were not randomized, conclusions must be interpreted within the context of the quasi-experimental design used in the current study.