Frequency and change mechanisms of psychotherapy among depressed patients: a multicenter randomized trial? (WC2014-040)


Starting date: 01/11/2014

Background of the study:

Recently, a strong association was found between the number of psychotherapy sessions per week and treatment outcome. However, there is no clarity about the optimal session frequency neither about the change mechanisms in the effects of psychotherapy. Finding an effect for session frequency will lead to higher therapy efficacy and lower the economic burden for depression while understanding the processes that account for therapeutic change might make us better able to optimize treatments.


Objective of the study:

The effectiveness of psychotherapy can be improved by increasing the frequency of sessions at the beginning of therapy. In addition, understanding processes that account for therapeutic change might enable us to optimize treatments.


Study design:

Multicenter randomized trial with four parallel groups (n=230) : a) twice-weekly sessions at the start of CT, b) twice-weekly sessions at the start of IPT, c) once-weekly sessions at the start of CT, d) once-weekly sessions at the start of IPT. Randomization (patient level) will be pre-stratified according to severity (high severity = BDI score =>30; low severity = BDI score <=29).


Study population:

230 depressed patients with a major depressive disorder (MDD) aged 18-65 years seeking treatment recruited from several Dutch mental health centers.


Intervention : 
Twice-weekly sessions of cognitive therapy or interpersonal therapy at the start of therapy, up to 20 sessions in total. Standard intervention to be compared to: once-weekly sessions of cognitive therapy or interpersonal therapy at the start of therapy, up to 20 sessions in total.


Primary study parameters/outcome of the study:

Depression (BDI-II) and quality of life (EQ-5D (5L)) will be the main outcome measures over the course of two years. Besides the completion of a clinical interview at baseline, patients will complete monthly assessments during the first six months of the study. There will be follow-up assessments 9, 12 and 24 months after start of treatment. For the patients who are willing to participate, blood samples will be collected during baseline and end of treatment.


Secundary study parameters/outcome of the study (if applicable):

The following secondary study parameters will be involved in the study: Therapeutic alliance (Working Alliance Inventory), cognitive skills (Competencies of Cognitive Therapy Scale/Performance of CT Strategies ), interpersonal skills, recall (patients recall of the last session rated by the therapist), motivation for therapy (Autonomous and Controlled Motivation for Treatment Questionnaire), compliance (amount of no-show and rated by patient and therapist), emotion regulation (Action Control Scale), executive functioning (n-back task), automatic thoughts (Cognition Checklist ), behavioral activation (Behavioral Activation for Depression Scale) and biological factors (brain-derived neurotrophic factor (BDNF), DNA methylation of CpG islands adjacent to promoters I and IV) and oxytocin.


Nature and extent of the burden and risks associated with participation, benefit and group relatedness (if applicable):

Patients will be invited to a clinical screening interview. Other measurements will be administered online, which guarantees maximum flexibility for the participant. Participation to the venipuncture will be an optional part of the study. Though the burden includes a time investment of the patient, no risks are associated with participation in the study.