Reasons for antidepressant nonadherence among veterans treated in primary care clinics

To examine the experiences of veterans (mostly middle-aged and elderly men) prescribed antidepressants, specifically with regard to different types of nonadherence, reasons for nonadherence, and side effects.

A mixed-methods analysis of Department of Veterans Affairs primary care patients (N = 395) with depression (9-item depression scale of the Patient Health Questionnaire criteria) enrolled in a randomized collaborative care trial was conducted. Adherence was measured from patient self-report and pharmacy data. Qualitative interviews elicited in-depth information regarding adherence. The study was conducted from April 2003 to September 2005.

The intervention significantly improved self-reported adherence at 6 months (OR = 2.1; 95% CI, 1.0-4.4; P = .04) and 12 months (OR = 2.7; 95% CI, 1.4-5.4; P < .01), as well as medication possession at 12 months (OR = 1.82; 95% CI, 1.0-3.2; P = .04). The most common type of nonadherence at 6 months was discontinuation (12.2%), followed by not taking as prescribed (10.9%) and never took (4.8%). For patients discontinuing their antidepressant in the first 6 months, the most common and important reason was that it was not helping. Only 19.4% of patients with self-reported adherence ≥ 80% responded to treatment by 6 months. Side effects were also a commonly reported reason for discontinuation at 6 months, with 82% reporting experiencing side effects. One-third (31.4%) reported difficulty with sexual activity at 6 months, with 66.1% reporting that it was severe. Qualitative interviews supported the finding that side effects, and generally not feeling like oneself, are important adherence barriers.

In this sample of mostly middle-aged and elderly men with depression, treatment nonresponse and side effects were the rule rather than the exception. These findings suggest that nonadherence may have resulted primarily from patients' negative experiences with antidepressants rather than structural barriers or noncompliant behaviors.

Clinicaltrials.gov Identifier: NCT00105690.