Comparison of Different Adherence Measures in Adolescent Outpatients with Depressive Disorder

Purpose: Adolescent depression can have a chronic course; hence, the importance of adherence to antidepressant medication for successful treatment outcomes is emphasized. This study aimed to examine different adherence measures and identify clinical factors that influence adherence in adolescent depression. Patients and Methods: A prospective study was conducted for patients diagnosed with depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition from outpatient psychiatric settings at Korea University Medical Center, Guro Hospital. Patient demographics were obtained from a questionnaire, interview, and review of chart records. Adherence was assessed by four methods (Medication Event Monitoring System [MEMS], pill count, clinical rating scale, and patient's self-report). The Toronto Side Effect Scale was used to evaluate side effects, and specific depressive symptoms were assessed using the Hamilton Rating Scale for Depression and Childhood Depression Inventory-Korean version. The Multidimensional Scale of Perceived Social Support was administered to analyze social support, and the Parenting Stress Index-Short Form was used to evaluate parental stress levels. We used concordance correlation analysis to evaluate the relationship among the four adherence measures and the relationship between adherence level and clinical factors. Results: Overall, the study enrolled 48 outpatients (mean age 16.33 +/- 1.93 years). The mean duration of illness was 1.27 +/- 2.17 years. Adherence rates for MEMS, clinician rating scale, pill count, and self-report after conversion to dichotomous measures were 67.5%, 48.9%, 60.0%, and 56.3%, respectively. Only the duration of illness remained significantly correlated with MEMS (r = 0.510, p =0.001). Conclusion: Pill count exhibited a higher degree of agreement with MEMS adherence than the other two adherence measures, possibly indicating that pill count may be a considerably reliable measure of adherence. Furthermore, MEMS adherence was positively correlated with disease duration, suggesting that the longer the duration of illness, the higher the adherence.