The review by Australian investigators in the International Journal of Clinical Practice identified 26 randomized controlled studies published since 1990 (25 conducted in the United States) that evaluated 28 interventions to improve adherence to antidepressant treatment.1 The researchers sought to distinguish between the interventions for relative effect on 2 components of adherence:
• Compliance with medication directions
• Persistence in taking the medication throughout the intended course of treatment
The authors also considered whether the interventions were associated with improved clinical outcome.
The researchers found that 16 of the 28 interventions were associated with significantly improved adherence, and 12 were associated with improvement in both medication adherence and clinical outcome. Their findings were similar to those of several earlier studies, which suggest that multifaceted interventions are superior to single-mode strategies. Educational strategies that were employed alone were not effective in improving adherence, despite being associated with improved satisfaction with, and attitude toward, treatment.
Distinguishing among interventions
Chong and colleagues1 describe the interventions, experimental groups and settings, and outcome measures. They classify the interventions as educational, behavioral, or affective and exclude from their analysis those that principally targeted the provider. The educational approaches were verbal or written knowledge-based designs to convey information; behavioral strategies intended to shape or reinforce patterns of behavior conducive to medication adherence; and affective interventions that appealed to feelings and emotions or social relationships and social supports.
Of the 22 multifaceted interventions, 11 evidenced positive effects on both medication adherence and depression outcomes relative to the control groups receiving usual care. Four of the 22 appeared only to benefit adherence; 4 others were associated with improvement in depression outcome without improving adherence; and 3 were not associated with improvement in either measure.
All but one of the interventions were conducted in primary care patients. The intervention conducted in a psychiatric practice employed telephone-based care management by nurses and did not result in improved adherence or clinical outcomes. The one behavioral intervention, the Treatment Initiation and Participation Program, was described as patient-provider collaboration to empower the patient to self-manage his or her own medication treatment. This psychosocial intervention in a population of older adult patients with late-life depression demonstrated positive results in both adherence and clinical outcomes.
The disappointing results with the use of just the educational strategies might be attributed to the imperson-al nature of some of the materials or how they were conveyed. That some multifaceted approaches were associated with improved outcomes but not adherence reflects the many factors that can influence clinical outcome.
“It may be possible that some of the multifaceted interventions addressed these other factors and therefore had a direct therapeutic benefit that was not mediated through improved medication adherence.”
The investigators note that depression is projected to be the second leading cause of disability worldwide by 2020, and that the World Health Organization has recognized depression as 1 of 9 chronic conditions for which interventions are required to improve medication adherence. Referencing data that indicate that approximately one-third of patients treated for depression in primary care stop taking their medication in the first month of treatment,2 they commented, “the premature discontinuation of antidepressant therapy has been linked to poor treatment outcomes such as increased risk of relapse and recurrence, as well as increased health care cost.”
