Participants were primarily recruited at the Massachusetts General Hospital OCD Clinic, through posted flyers in the Boston communities. However, two of the enrolled patients were recruited through the University of Virginia because the fifth author relocated there, from MGH, during the course of the study. All participants were age 18 or older, met American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (4th ed.) criteria for a primary diagnosis of OCD, and had Yale-Brown Obsessive-Compulsive scale scores of >16. Individuals with primary hoarding were not admitted into the study. Individuals were ineligible if they reported current suicidal or psychotic symptoms or other features necessitating psychiatric hospitalization, Tourette's Disorder, or showed evidence of mental retardation, dementia, brain damage, or other severe cognitive dysfunction. We also excluded those who were currently engaged in psychotherapy, had previously received CT for OCD, or had been unsuccessfully treated with an adequate trial (10 or more sessions) of BT. The latter two exclusion criteria were required by The National Institute of Mental Health (NIMH) reviewers to avoid initial testing of the efficacy of this new treatment in a treatment resistant sample. Individuals receiving psychopharmacological treatment could participate if they had been stably on or off medication for at least 2 months preceding study enrollment and remained stable throughout the trial.
Of 31 participants who enrolled, two were found ineligible after starting treatment and were removed from the trial. The 29 eligible participants (15 women) had a mean age of 33.4 (SD = 11.2; range = 18 to 68), and a mean Y-BOCS score of 25.6 (SD = 4.8). Twelve patients had concurrent DSM-IV comorbid conditions including major depression (n = 7), generalized anxiety disorder (n = 4), social phobia (n = 3), specific phobia (n = 2), body dysmorphic disorder (n = 1), and dysthymia (n = 1). Fourteen patients were taking psychotropic medication: clonazepam (n = 4), fluvoxamine (n = 3), citalopram (n = 2), escitalopram (n = 2), paroxetine (n = 2), sertraline (n = 2), alprazolam (n = 1), buproprion (n = 1), clomipramine (n = 1), fluoxetine (n = 1), and venlafaxine (n = 1).