Turning prevention into a challenge Towards a new integrated model of depression prevention

Depressive-, and anxiety disorders are common and debilitating conditions. In order to improve outcomes for people at risk of onset, relapse or recurrence, it is necessary to identify robust, personalised, strategies that are most effective at reducing this risk. This thesis set out to study the effects of interventions that aimed to prevent the onset of common mental health conditions and relapse/recurrence of depression. It aimed to identify what works for whom via a range of systematic reviews, scoping reviews and individual participant data meta-analysis.
In the first part of this thesis, which focussed on onset (primary) prevention, the effectiveness of interventions to prevent depression among young adults were examined. In addition, it was studied whether neighbourhood social cohesion could protect against depression and anxiety in adolescents and young people. To conclude the first part of this thesis, a systematic review was conducted that evaluated the type of outcome measurement used in onset prevention studies for common mental health conditions.
In the second part of this thesis, which focussed on relapse prevention, we explored the relative efficacy of the leading strategies employed for relapse prevention of depression, namely psychological interventions with and without antidepressants. Successively, an individual participant data meta-analysis studied whether demographic and clinical factors could inform to whom to recommend a psychological intervention while tapering antidepressants and to whom to recommend continuation of antidepressant medication.
Based on the results of this thesis and an analysis of past models of prevention, this thesis presents a novel integrated model of prevention which suggests that integrating both phases into one model can help advance future research and understanding of depression prevention.