Practice recommendations
- Educating your patients on how to take their antidepressant medication helps adherence.
- Primary care physicians may be able to improve patient adherence to antidepressant medications by telling patients how long they will have to take them, letting them know about possible side effects, and addressing their questions and concerns.
Nonadherence to antidepressants among patients with depressive disorders has been reported to be as high as 68%.1 While research on the efficacy and effectiveness of depression treatments is voluminous, research on factors associated with antidepressant adherence is much more limited.2,3
Several studies have pointed to the importance of patient education regarding antidepressants in improving adherence.4,5 Previous studies have found that rates of antidepressant adherence4 and medication discontinuation1 were significantly associated with the how much information the physician gave the patient about the drug’s use. However, a review of interventions to improve adherence concluded that patient education required further study.6
In this study, we prospectively examined whether patient reports of specific educational messages from their primary care physician on antidepressant usage was associated with medication adherence during the first 3 months of treatment. To monitor adherence, we used electronic monitoring caps rather than self-report. Based upon prior work examining predictors of adherence,4 we hypothesized that patients who received specific messages about how to take their medicine would demonstrate greater adherence during the first 3 months of treatment.
Implications
Findings support hypothesis
We found a significant dropoff in adherence to prescribed antidepressants during the first 3 months of treatment. We also found support for our hypothesis that patients who received specific messages from their physicians would be more adherent to their drug regimen. We were able to identify several key messages that were associated with at least 80% adherence over a 3-month period. The most important messages were: How long the patient should expect to take the medicine and what to do if there are questions. Other important messages included being told to keep taking the medication even if feeling better, being advised as to how long side effects would last, and being given advice on managing minor side effects.
Methods
Participants
We enrolled 191 primary care patients in a year-long observational study. All participants were referred to the parent study by their primary care physicians.
Patients were eligible for referral if they were age 18 years or older; had been prescribed an antidepressant for the treatment of depression in the preceding 2 weeks or had been switched to a new antidepressant within the preceding 2 weeks; had no lifetime history of bipolar disorder; had no substance abuse or dependence in the preceding 6 months; or had no current psychotic symptoms or history of psychotic disorder. The study protocol was approved by the University of Pittsburgh Institutional Review Board and the Veteran’s Affairs Institutional Review Board. All participants provided written informed consent.
Participants were recruited from 2 urban family practice health centers: a single-specialty group practice and 2 primary care clinics in the Veterans Health Administration (VHA). This report focuses on data obtained through interviews and questionnaires at the baseline evaluation (n=191) and adherence data from the first 3 months of the study (n=178).
Measures
Information on race, gender, education, employment, marital status, and income was obtained from each participant. A semistructured interview was administered to assess the presence of current mood, anxiety, substance use, and somatoform disorders.7
Severity of depressive symptoms was evaluated with the 21-item Beck Depression Inventory. Psychosocial and physical functioning was assessed with the 36-item, self-administered Medical Outcomes Study Short Form General Health Survey (MOS SF-36). The MOS scales were weighted and aggregated into the scores for the Physical Component Scale (MOS PCS) and the Mental Component Scale (MOS MCS).8
Medical conditions were assessed with a modified version of a checklist developed by Wells et al for use in the Medical Outcomes Study.9 The modified list assessed the presence of hypertension, diabetes, coronary artery disease, angina, arthritis, back problems, pulmonary problems, gastrointestinal disorders, cancer in the preceding 3 years, major neurological problems, cardiac pacemaker, kidney disease, legal blindness, eye disease, thyroid disease, lupus, and HIV/AIDS.
Electronic caps track adherence
At baseline, patients were given their medications in bottles with electronic monitoring caps. The Medication Event Monitoring System (MEMS) cap made by Advanced Analytical Research on Drug Exposure (AARDEX), is a standard-looking childproof cap fitted with a microprocessor that records the date and time the cap is removed from the bottle and the amount of time until it remains off. Using this data, we calculated 2 adherence scores: the percentage of prescribed doses taken and the percentage of days with correct intake and timing over a 3-month period.