Optimizing psychotherapy dosage for comorbid depression and personality disorders (PsyDos): a pragmatic randomized factorial trial using schema therapy and short-term psychodynamic psychotherapy.

Background: Patients with comorbid depression and personality disorders suffer from a heavy disease burden while tailored treatment options are limited, accounting for a high psychological and economic burden. Little is known about the effect of treatment dosage and type of psychotherapy for this specific co-morbid patient population, in terms of treatment-effect and cost-effectiveness. This study aims to compare treatment outcome of 25 versus 50 individual therapy sessions in a year.