Objectives: Adherence to medication is regarded as an important factor for predicting clinical outcomes in mental disorders such as depression, bipolar disorder or schizophrenia. The current study investigates the relation between adherence and the burden of depression on society and individuals. Methods: Data were from the 2013 EU National Health and Wellness Survey (NHWS), an internet-based survey from a representative sample of adults from France, Germany, Italy, Spain and UK stratified by age and gender. Out of 62,000 respondents, 8,462 (11%) reported a diagnosis of depression and 3,937 (6%) having a prescription medication for depression (Rx). Respondents classified as adherent according to the Morisky Medication Adherence Scale (MMAS) were compared to the non-adherent on severity (PHQ-9), sociodemographics, health characteristics, health-related quality of life (SF-36), work productivity and activity impairment (WPAI) and health care resource use (physician, hospital and emergency visits). Results: Compared to adherent respondents (54%), the non-adherent (46%) were more severe (37% vs. 31% with PHQ-9 score (greater-than or equal to) 15); had lower Mental Component Summary (MCS: 32 vs. 33); higher Absenteeism (18 vs. 16); more emergency visits in the previous 6 months (0.49 vs. 0.42); and their satisfaction with medication was lower (4.97 vs. 5.27) (All p< 0.05). About 75% of both groups were participating in psychotherapy at the time of survey and showed no significant difference in Physical Component Summary (PCS); Presenteeism; and number of hospitalizations. Conclusions: While efficacy measured during clinical trials is one of the most influential measures in treatment assessment, its ecological validity may be jeopardized by non-adherence to medication in real life. The current study shows that low adherence is associated with more severe depression, lower treatment satisfaction and lower mental quality of life (MCS) in respondents taking antidepressants. These results point at the importance of combining adherence and efficacy in the assessment of treatments for depression.
Pedersini, R., & Kuehl, M. (2014). The Burden Associated with Non-Adherence in European Patients with Depression. Value in Health, 17(7), A329. https://doi.org/10.1016/j.jval.2014.08.606