Measurements were taken at baseline (T0), and at posttreatment after 3 months (T1). In order to study the stability of the effect of MBCT, the patients in the experimental group received a follow-up measurement (T2) at 6 months after baseline. For the control condition, the measurement at 6 months is a posttreatment measurement. All measurements had good psychometric properties and are frequently applied in international studies. The primary outcome measure was depressive symptomatology, measured by the Dutch version of the Center of Epidemiological Studies - Depression Scale (CES-D; 20 items, score 0–60) [24]. Higher scores mean more depressive symptoms [24,25].