Recruitment and Selection

Participants were recruited at the Centre for OCD of the Ghent University Hospital (UZ Gent) located in Belgium. All patients had previously been diagnosed with OCD by expert psychiatrists and clinical psychologists using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, Fourth or Fifth Edition (DSM-IV or DSM-5), as reported in their electronic medical records. Inclusion criteria were: (a) diagnosis of OCD, (b) age of patients between 18 and 65 years old, (c) speaking Dutch fluently. Exclusion criteria were: (a) current substance abuse and (b) psychotic symptoms. In addition, Dutch speaking family members, aged 18-65 years old, who were living in the same household as the patients with OCD were asked to participate in the study. This study was approved by the Ethical Committee of the Ghent University Hospital (UZ Gent, BC-07561).