Randomised controlled trial to evaluate the effectiveness of collaborative care in a Dutch occupational healthcare setting: 126 workers on sick leave with major depressive disorder were randomised to usual care (n = 61) or collaborative care (n = 65). After 3 months, collaborative care was more effective on the primary outcome measure of treatment response (i.e. reduction in symptoms of ≥50%) on the Patient Health Questionnaire-9 (PHQ-9). However, the groups did not differ on the PHQ-9 as a continuous outcome measure. Implications of these results are discussed.