Improving Psychotherapy Dosing for Comorbid Depression and Personality Disorders

Researchers are conducting a trial to determine whether 25 or 50 psychotherapy sessions in a year will be more effective at reducing symptoms of depression in patients with personality disorders.

Determining optimal dosing for psychotherapy remains a challenge in patients with comorbid depression and personality disorders. An ongoing study published in BMC Psychiatry aims to provide insight about the effects of treatment dosage and type of therapy in this population.

The ongoing trial includes 200 participants between the ages of 18 and 65 diagnosed with a depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) and 1 or more DSM-5 personality disorders. By means of a 2×2 factorial design, study participants are randomly assigned to 2 different amounts of psychotherapy sessions (25 vs 50 psychotherapy sessions in 1 year) and type of treatment (Schema Therapy [ST] vs Short-term Psychodynamic Supportive Psychotherapy [SPSP]).

The primary outcome measure is depression severity and remission, assessed using the Beck Depression Inventory-II (BDI-II) and Mini-International Neuropsychiatric Interview (MINI-plus) sections A and B. Secondary outcomes include changes in personality parameters and quality of life.

Study participants will be unable to obtain additional psychotherapy during the trial, as the assigned dosage would be modified; however, participants may still be given pharmacologic treatment after psychiatrist consultation, if indicated. All pharmacotherapy prescribed during the trial will be monitored by study investigators.

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A primary limitation of the study is the lack of a treatment-as-usual (TAU) condition for comparison; however, because psychotherapy will be given for a year, the investigators rationalized that incorporating a condition is not feasible for this trial.

The researchers explained that “this is the first study to compare 2 psychotherapy-dosages in this comorbid patient group.” They expect the results to “help get insight in[to] how frequent and how much psychotherapy is needed to treat these complex patients.”


Kool M, Van HL, Bartak A, et al. Optimizing psychotherapy dosage for comorbid depression and personality disorders (PsyDos): a pragmatic randomized factorial trial using schema therapy and short-term psychodynamic psychotherapy. BMC Psychiatry. 2018;18:252.