Personality traits as predictors of exercise treatment adherence in major depressive disorder: lessons from a randomised clinical trial.

Objective: The objective of this study was to explore the determinants of adherence in the EFFORT-D (EFFect Of Running Therapy) study in a specialised mental health care hospital setting.

Methods: Patients with major depressive disorder (MDD) were given treatment as usual and half were randomised to an exercise intervention. Adherence was measured at 3 months (T3) and 6 months (T6) and was defined as participation in the overall study protocol (total  = 42, adhered  = 28) or intervention (total  = 24, adhered  = 9). Potential determinants were age, BMI, tobacco and alcohol use, severity of depression, anxiety, fitness (VOmax kg and Wmax kg) and personality traits at baseline. ANOVA, Chi-square tests and block-wise logistic regression were performed, and reliability of the scales was determined.

Results: Numbers were found too low for analyses on smoking, drinking and anxiety. Higher agreeableness was significantly associated with better adherence to the overall study protocol (OR 1.2;  = 0.03; 95% CI: 1.01-1.4) and severity of depression was negatively associated with adherence in the intervention group (OR 0.70;  = 0.046;95% CI: 0.49-0.99).

Conclusions: To adhere to a study protocol involving exercise or to a clinical exercise programme, MDD patients need substantial personal support. Measurement of personality traits and the severity of depression as potential predictors of adherence could be considered for this purpose. Keypoints Adherence to exercise and study protocols in a randomised controlled trial was low Patients with severe major depressive disorder need substantial personal support Measurement of personality traits could be considered.