Post-hoc analysis of psychotherapy outcome data suggest that psychodynamic techniques for Major Depressive Disorder are differentially efficacious dependent on personality traits of the patient. More specifically, supportive techniques are hypothesized to be more efficacious for dependent patients, interpretative techniques to be more efficacious for self-critical patients, and mixed supportive/interpretative techniques to be more efficacious for mixed dependent/self-critical patients. Moreover, supportive techniques are hypothesized to impact on depressive symptoms through increased relational capacities while interpretative techniques impact through increased self-understanding.

These hypotheses are tested in an experimental single case design with three dependent, three self-critical and three mixed dependent/self-critical depressive patients. These patients go through a time-limited (50 sessions) experimental treatment which exists of a sequence of four A phases (control conditions), one B phase (supportive techniques only), one C phase (interpretative techniques only), and one BC phase (mixed supportive/interpretative techniques).

Inclusion Criteria:

• Patient meets criteria for Major Depressive Disorder (as assessed by SCID-I and DSM-IV-TR)
• Patient is prepared to give informed consent

Exclusion Criteria:

• Patient uses antidepressant medication during the treatment
• Patient scores 3 on the suicide item of the BDI-II
• Patient meets criteria for psychotic or personality disorder (as assessed by SCID-II)