Four-day Intensive Treatment Versus Standard Cognitive Behavioral Therapy for Adults With Obsessive-compulsive Disorder

The goal of this clinical trial is to compare a novel, condensed version of cognitive behavioral therapy (Bergen 4-Day Treatment, B4DT) to the gold standard psychological treatment (gold-standard CBT) for obsessive compulsive disorder (OCD).The main question it aims to answer is:• Is B4DT non-inferior to standard cognitive behavioral therapy (CBT) with regard to OCD symptoms 14 weeks after treatment start?Adult patients with obsessive compulsive disorder will be randomly assigned to receive either gold standard CBT one to two times per week for 14 weeks, or 4 days of B4DT during one week.

Inclusion Criteria:≥ 18 years of age.Primary diagnosis of OCD according to the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5).Clinician-rated Y-BOCS score of ≥ 16Written informed consent.To be willing and able to attend treatment at any one of the two treatment clinics, regardless of the clinic where the initial assessment took place (the two clinics are located at different locations in Stockholm, about 20 Km apart).Be fluent in Swedish.Exclusion Criteria:Other psychological treatment for OCD planned during trial period.Completed CBT with ERP for OCD in the last 12 months.Changes in psychotropic medication within the last 2 months.Bipolar disorder.Psychosis.Alcohol or substance dependence.Organic brain disorder.Hoarding disorder or OCD with primary hoarding symptoms.Suicidal ideation that would warrant close monitoring.