Improving adherence to antidepressants: A systematic review of interventions

Background: Effectiveness of antidepressant medication is reduced by patients' nonadherence. Several interventions to improve adherence in patients diagnosed with unipolar depression have been tested. Objective: To systematically review the effectiveness of interventions that aimed to improve adherence to antidepressant medication in patients with unipolar depression. Method: Systematic review of English-language articles of randomized controlled trials obtained by a computerized literature search of MEDLINE (1966-January 2002) using the terms patient compliance, patient dropout, treatment refusal, patient education, adherence, clinical trial, randomized controlled trial, controlled trial, depressive disorder, and depression; PSYCINFO (1984-January 2002) using the terms random, clinical, control, trial, adherence, compliance, noncompliance, dropouts, patient education, depression, major depression, affective disorders, and dysthymic disorder; EMBASE (1980-January 2002) using the terms patient compliance, patient dropouts, illness behavior, treatment refusal, patient education, clinical trial, controlled study, randomized controlled trial, and depression; and the Cochrane Controlled Trials Register (no restrictions) using the terms random*, complian*, adheren*, pharmacotherapy, regimen*, educat*, medicat*, depression, and depressive disorder. Results: Educational interventions to enhance adherence failed to demonstrate a clear benefit on adherence and depression outcome. However, collaborative care interventions tested in primary care demonstrated significant improvements in adherence during the acute and continuation phase of treatment and were associated with clinical benefit, especially in patients suffering from major depression who were prescribed adequate dosages of antidepressant medication. Conclusion: We found evidence to support the introduction of interventions to enhance adherence with antidepressant medication in primary care, not only because of better adherence but also because of better treatment results. Because collaborative care interventions require additional resources, a better understanding of the mode of action of different programs is needed to reduce avoidable costs. The effectiveness of educational interventions needs more evidence.