Variables influencing antidepressant medication adherence for treating outpatients with depressive disorders

Medication adherence is associated with the treatment outcomes. The reported consequences of non-adherence for patients with depressive disorders include chronification, poor psychosocial outcomes and increased suicide rates. The aim of this study is to determine whether insight is directly associated with the medication-taking adherence of patients with depressive disorders. In addition, we compared the various kinds of adherence measures for the depressive patients.

Consecutively 76 patients with depressive disorders were recruited from the outpatient clinic of our center. All patients were on mono-antidepressant therapy during at least 4-weeks' evaluation period, and evaluated with 17 item Hamilton Rating Scale for Depression (HRSD), Multidimensional Scale of Perceived Social Support (MSPSS) and Mood Disorders Insight Scale (MDIS). Medication adherence was assessed by using medication event monitoring system (MEMS), clinician rating scale of antidepressant adherence, pill count and patient's self-report. Agreement among the three continuous adherence measures was evaluated. The relationship between the adherence variables and the other clinical scale scores was assessed by using partial correlation correcting for age.

The patients perceived poor social support from other people in relation to increasing severity of depression. The adherence rates for the MEMS, the pill count, the clinician rating scale of compliance and self-report were 51.9%, 71.4%, 79.2% and 75.3%, respectively. The HRSD scale score negatively correlated with the MDIS scores. No correlation was found between the adherence variables and the clinical scale scores (MDIS, HRSD and MSPSS).

Patients with more severe depression tend to have greater insight. However, the increased insight of depressive patients was not associated with an increase in treatment adherence.