D*Phase psychotherapy study: efficacy of short-term psychodynamic therapy versus cognitive-behavioral therapy for major depression A randomized clinical trial adressing predictors, moderators and initial treatment non-response

INTERVENTION: During the 8 week period of the first part of the study, subjects will be offered 16 treatment sessions of SPSP or CBT. In the second part of the study, the patients who did not respond after the first 8 week period of psychotherapeutic treatment (as defined bij less than 50% reduction compared to the initial score on the primary outcome measure), will then again receive the same number of treatment sessions, during another 8 week period. One third of the patients will continue treatment and stay with the same therapist, as during part 1 of the study. One third will continue the same treatment but will switch therapist, for the second part of the study. One third will switch to another therapist and the other form of psychotherapeutic treatment investigated in the study. CONDITION: Depressive Disorder ; ; PRIMARY OUTCOME: Severity of depressive symptoms, measured through a self‐report questionnaire (IDS‐SR; Inventory of Depressive Symptomatology ‐ Self Report) SECONDARY OUTCOME: Secondarily, we are interested in wellbeing and self‐reported disabilities and functional impairment. Both will also be measured through self‐report questionnaires (resp. MHC‐SF (Mental Health Continuum‐Short Form) and SDS (Sheehan Disability Scale ). ; INCLUSION CRITERIA: Subjects have to suffer from a moderate to severe Major Depressive Disorder according to the MINI (Mini International Neuropsychiatric Interview), which has to be the primary DSM‐IV‐diagnosis.