Interventions for psychosocial difficulties in depressionResearch recommendations for improving measurement of treatment effectiveness in depression

Abstract

Despite the continuously escalating psychological, societal and economic burden of depression, there is a lack of evidence regarding the effectiveness of available interventions on important functional areas beyond specific depressive symptoms. Therefore, the main objective of this thesis is to give an insight into the current measurement of treatment effectiveness in depression and to provide recommendations for its improvement. The first part of the thesis critically reviews the current measurement of treatment effectiveness in depression and provides a systematic assessment of the effectiveness of available psychological and pharmacological interventions on psychosocial functioning in depression. The section consists of three articles - a systematic literature review and two meta-analyses. The second part of the thesis is dedicated to the collection of empirical evidence designed as a response to all the limitations of the current research identified in the first part of the thesis. The evidence is collected from a multi-country cross-sectional study, a qualitative study with patients with depression, and an expert survey with representatives from clinical practice. At the end research recommendations for improving treatment effectiveness measurement in depression are provided. The effectiveness of available interventions for depression is assessed mainly in terms of reduction of clinical symptoms, whereas other areas of functioning are neglected. In addition, all interventions for depression perform better at reducing symptom severity than at improving areas of functioning others than symptomatology. Several limitations in research were identified – 1) a very small number of studies to apply functional outcome measures; 2) a majority of studies with poor quality; 3) heterogeneous instruments addressing distinct areas of functioning; 4) lack of long-term reports on the effectiveness of interventions; 5) high percentage of papers reporting sum-scores rather than domain-specific information; and 6) lack of personalized information on the effectiveness of specific treatments on specific areas of functioning or particular group of individuals. As an answer to these limitations, results from the multi-country epidemiological study revealed that there was a variation in the level of impairment in different functioning domains across countries. Gender differences in the functional impairment of depression were also found. Clinical experts and depressed patients highlighted the importance of both depressive symptoms and functional areas beyond symptoms. A set of the most important functional areas in depression, namely mental functions, sleep, energy level, somatic problems, interpersonal relationships and interaction, recreation and daily activities, communication, social participation, daily tasks and demands, work and educational difficulties, and personal factors such as self-efficacy or self-awareness was defined. In addition, clinicians and patients identified a number of differences regarding the areas improved by psychotherapeutic or pharmacological interventions that were not addressed by the pertinent literature. Five main recommendations for future improvement of the measurement of treatment effectiveness in depression were derived from the research we carried out. Firstly, a new instrument comprehensively assessing all relevant psychosocial difficulties in depression has to be created. Secondly, the new functional tool has to be cross-nationally applicable. Thirdly, report of domain-specific information has to be included in clinical trials. Fourthly, broader remission criteria for depression including psychosocial functioning beyond symptoms are needed. Finally, there is a need of a more personalized approach in treatment decision making, acknowledging specific patient needs and accounting for a more comprehensive array of functional domains.