Systematic Literature Review

Full details of the systematic literature review are provided elsewhere (Kamenov et al., 2015); a concise description is presented below. An electronic search for studies assessing interventions in depressive disorders was performed using four databases: PsycINFO, PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials. Studies published between 2005 and 2015 were identified by including a set of sensitive MeSH terms and keywords indicative for intervention, depression and functioning. Studies were included if (1) participants were older than 18, (2) the diagnosis of depression was established by a standardized diagnostic tool, and (3) the sample included at least ten participants.

We grouped the treatments into three main categories: psychotherapy, pharmacotherapy, and “other” therapies, such as sleep deprivation and exercise therapy (Patten et al., 2009). All primary and secondary outcome measures assessing functioning, QoL or severity of symptoms that were already validated in depression samples were selected, and all individual items of the selected tools were extracted. The extracted items were analyzed and were linked to the International Classification of Functioning, Disability and Health (ICF) for operationalization purposes by applying the established linking rules (Cieza et al., 2005). The linking process was performed by two researchers. The items were grouped into 10 overarching categories based on the ICF classification. A frequency analysis was conducted after all functioning problems were identified to present the percentage of the areas stratified by type of intervention.