Antipsychotic nonadherence is an important barrier to the successful treatment of schizophrenia and can lead to clinical and economic burdens. Interventions capable of significantly improving medication adherence in patients with schizophrenia would be beneficial in maximizing treatment outcomes with antipsychotics. This article reviews recent literature reporting interventions designed to improve antipsychotic adherence in patients with schizophrenia. We searched the Medline, Healthstar, and PsycInfo electronic databases for articles published since 1980 on interventions to improve medication adherence in schizophrenia. Twenty-one studies met our selection criteria. In this review, educational, behavioral, affective, or a combination of these approaches to improve adherence were exammed. A total of 23 interventions were tested, as 2 studies investigated more than 1 intervention. While study design and adherence measures varied across the trials reviewed, medication adherence was noted to moderately improve with 15 of the 23 interventions tested. Interventions of a purely educational nature were the least successful at improving antipsychotic adherence. The greatest improvement in adherence was seen with interventions employing combinations of educational, behavioral, and affective strategies with which improvements in adherence were noted in 8 out of 12 studies, with additional secondary gains such as: reduced relapse, decreased hospitalization, decreased psychopathology, improved social function, gains in medication knowledge, and improved insight into the need for treatment. Longer interventions and an alliance with therapists also appeared important for successful outcomes. The continuing development and study of successful interventions to improve medication adherence are necessary to maximize the usefulness of pharmacologic treatment of schizophrenia.
Schizophrenia is one of the most expensive mental disorders in terms of direct treatment costs, loss of productivity, and expenditures for public assistance. The annual cost of schizophrenia is estimated to be US $33-65 billion. 1,2 Currently, the most effective treatment for schizophrenia is symptomatic and usually involves the use of antipsychotic or neuroleptic medications. Unfortunately, even perfectly designed antipsychotic treatment regimens may fail due to nonadherence. Over the past several decades, the literature has increasingly recognized nonadherence as a contributing factor in the failure of prescribed antipsychotic regimens. Medication underuse is the most common problem associated with nonadherence in patients with schizophrenia. Deviation from antipsychotic maintenance treatment produces clinical and economic burdens such as psychotic relapse, increased clinic visits, emergency room visits, and hospitalization. 3,4
The reported rates of nonadherence to antipsychotic medication vary greatly. This may be explained, in part, by the different methods employed in the published literature. Some of the methodological differences relate to type of assessment (qualitative vs. quantitative, self-report vs. informant information, direct vs. indirect measurement), observation period (a week vs. several months), and criterion threshold for defining nonadherence (any deviation opposed to an acceptable range). Depending on the study design, measurement method, and other factors, reported rates of nonadherence to antipsychotic medication range from 11% to 80%, with an average rate of approximately 50%. 5,6 Adherence appears to remain a problem despite the use of atypical antipsychotics. We recently examined antipsychotic adherence for up to 12 months in middle aged and older veteran outpatients prescribed typical (haloperidol or perphenazine) or atypical (risperidone, olanzapine, or quetiapine) agents. Using refill records, we found 12-month mean compliant fill rates (proportion of adherent fills out of total fills) to be 50.1% for patients prescribed typical antipsychotics and 54.9% for those on atypical agents, a nonsignificant difference. 7 Over 200 variables have been examined in studies of medication nonadherence 8 and have been broadly categorized as patient-related, medication-related, and environment-related. 9 Modifiable factors consistently associated with nonadherence to antipsychotic medications should be considered targets for interventions. 5,6 In this paper, we review the interventions used to enhance antipsychotic adherence in chronic schizophrenia patients. While conducting our literature search, we identified only 1 recent review by Fenton et al 5 that comprehensively examined interventions to improve antipsychotic adherence. Thus, our paper represents an updated and comprehensive review on this topic because additional studies have been published since the scholarly paper of Fenton et al, and we summarize those studies included in this review.