OBJECTIVE: Patient participation in shared treatment decision-making is hypothesized to improve depression treatment adherence and clinical outcomes in depressed patients. The study aim was to evaluate the impact of patient participation on these factors and to determine the variance of clinical outcome as the primary outcome variable. METHODS: A survey was administered to 30 general practitioners and 207 depressed patients, at initial consultation and 6-8 weeks later. General practitioners documented their clinical practice and patients completed questionnaires including Brief-PHQ for depression and clinical outcome, patient participation scale, and visual analogue scales for treatment adherence. Assessment of correlations was followed by the development of a structural equation model (as a latent variable analysis) to define a model to explain the entire set of the variables' relationships. RESULTS: Sixty percent of the variance in clinical outcome was attributable to patient adherence (beta=0.41) and baseline depression severity (beta=0.65). Depression severity predicted clinical outcome but not patient participation. Participation predicted adherence (beta=0.39) but did not directly affect clinical outcome. Adherence was explainable by physician- (beta=0.57) and patient-reported treatment adherence (beta=0.66). CONCLUSION: In a specific pathway via adherence, patient participation in decision-making influences clinical outcome in primary care of depression. PRACTICE IMPLICATIONS: The research findings reveal the significance of patient participation as a key factor to address for improving treatment adherence and clinical outcome. Quality improvement strategies for depression treatment should emphasize patient participation.
