Depression is a common disease among young and older adults. Although it can be treated, non-adherence is very common among individuals of different ages. The aim of the present paper is to review and summarize research findings regarding depression among young and older adults, with a special focus on the phenomenon of treatment non-adherence among young and older adults with depression. The first section of the review focuses on describing the characteristics of depression in young and older adults. The second section focuses on treatment non-adherence of young and older adults, the prevalence of this phenomenon, and its consequences. The third section focuses on several factors (illness beliefs, treatment beliefs, self-stigma, and self-esteem) that were identified as having a significant association with treatment non-adherence of individuals with depression, with special attention focused on age differences. Results of the review of the literature reveal that research in the area of depression treatment non-adherence and its predictors among young and older adults has received, to date, very minor and limited attention. Thus, there is a need to expand the current body of knowledge and promote future interventions geared towards the unique characteristics of depression among young and older adults, in order to increase their treatment adherence.
Keywords: age differences; depression; treatment adherence.