Evaluation of factors influencing medication compliance in inpatient treatment of psychotic disorders

Rationale: Short- and long-term compliance to prescribed antipsychotic drugs is of particular concern in regard to medication choice and treatment outcome in the care of psychotic disorders. Objective: We evaluated patient-related and treatment-related factors associated with medication compliance in inpatients with a diagnosis of schizophrenia, schizoaffective disorder, or other psychotic disorder. Methods: Within a naturalistic study in seven psychiatric hospitals, individuals with a psychotic disorder were assessed weekly on mental state, social functioning, side effects, and medication compliance. Logistic regression analyses were computed to assess patient and clinical predictors of medication compliance. Results: We found a significant association between medication compliance and substance abuse (OR 0.52, CI 0.32-0.85), involuntary admission (OR 0.60, CI 0.41-0.89), history of aggressive behavior (OR 0.57, CI 0.38-0.85), and no school graduation (OR 0.59, CI 0.41-0.86). Individuals with pronounced paranoid or negative symptoms were also less compliant in taking their prescribed medication. There was no association between the initial inpatient antipsychotic medication regime and patients' compliance. Individuals who switched from a typical to an atypical antipsychotic drug were more compliant than those with their typical antipsychotic drug maintained. Those with higher medication compliance showed significantly greater improvement of their psychiatric symptoms during the inpatient stay. Conclusions: Patient-related in addition to disease-related factors may strongly influence medication compliance. Besides more compliance with atypicals supposed by the literature, there may be a higher propensity for atypical drugs to be prescribed to those assumed to be more compliant.