Partial Adherence to Antipsychotic Medication Impacts the Course of Illness in Patients With Schizophrenia: A Review

The failure by patients to take medication as prescribed is a phenomenon that is well known to clinicians in all medical specialties. Among patients with schizophrenia, adherence issues can severely limit the clinical improvement that is achievable with even the best available treatments. There is, however, no evidence that the situation has improved over the last 30 years, and, despite the introduction of new medications with improved tolerability profiles, poor adherence remains a problem. This may be because in both clinical research and day-to-day practice, adherence has often been portrayed as an all-or-nothing issue, with patients being regarded as either adherent or nonadherent. When considering interventions for adherence problems, clinicians have therefore tended to focus on those patients who openly refuse or repeatedly discontinue treatment and are regarded as difficult-to-treat cases. While this description applies to only a limited proportion of patients, in our experience, full adherence is rare. In reality, most patients are partially adherent to some extent, but the focus on treatment discontinuation may have led clinicians to discount partial adherence as an issue worthy of their attention, perhaps regarding it as inevitable and unavoidable. Unless clinicians appreciate the impact that relatively minor deviations from prescribed treatment regimens can have on treatment outcomes,1 they are unlikely to take the problem seriously or to devote sufficient time and attention to addressing suspected adherence problems among their patients. Notably, treatment adherence is considered to have a major influence on achieving clinical remission.2 Failure to achieve remission is a predictor for poor prognosis, psychiatric complications, treatment resistance, and even death from medical comorbidities and suicide.3 Moreover, patients who fail to take their medication as prescribed are at a greatly increased risk of relapse.1,4,5 Given the devastating impact of psychotic relapse on the course of illness, relapse prevention strategies should encourage greater awareness of the impact of partial adherence and should incorporate appropriate steps to minimize or eliminate the problem, particularly during the early stages of the illness. This article examines the issue of adherence behavior and its impact on treatment outcomes, with particular reference to early psychosis and first-episode patients, and provides observations on suggested strategies for managing these issues in patients with schizophrenia. A search of the published literature from 1980 to 2008 was performed using the PubMed search engine. Articles written in English (original research and reviews) were identified using the following keywords: schizophrenia or psychosis combined with compliance, noncompliance, partial compliance, adherence, nonadherence, or partial adherence. Additional references were identified through citations in relevant articles.