• Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) [ Time Frame: Measured at Months 1 and 3 post-treatment ] [ Designated as safety issue: Yes ]
• Treatment-related cost estimates [ Time Frame: Measured at Months 1 and 3 post-treatment ] [ Designated as safety issue: No ]

• Measured 1 and 3 months post-intervention: Yale-Brown Obsessive-Compulsive Scale (Y-BOCS)
• Treatment-related cost estimates

• Clinician's Global Impression (CGI) [ Time Frame: Measured at Months 1 and 3 post-treatment ] [ Designated as safety issue: Yes ]
• Beck Depression Inventory-II (BDI-II) [ Time Frame: Measured at Months 1 and 3 post-treatment ] [ Designated as safety issue: Yes ]
• Sheehan Disability Scale (SDS) [ Time Frame: Measured at Months 1 and 3 post-treatment ] [ Designated as safety issue: No ]
• Quality of Life Inventory (QOLI) [ Time Frame: Measured at Months 1 and 3 post-treatment ] [ Designated as safety issue: No ]

• Measured 1 and 3 months post-intervention: Clinician's Global Impression (CGI)
• Beck Depression Inventory-II (BDI-II)
• Sheehan Disability Scale (SDS)
• Quality of Life Inventory (QOLI)

This study will determine the effectiveness and cost-effectiveness of a stepped-care treatment program for people with obsessive-compulsive disorder.

Obsessive-Compulsive Disorder (OCD) is a chronic and debilitating anxiety disorder. People with OCD often experience recurrent unwanted thoughts, called obsessions, and repetitive behaviors, called compulsions. These thoughts and behaviors interfere with everyday life to a great extent. Currently, the most frequently used psychosocial treatment for OCD is cognitive-behavioral therapy (CBT) that incorporates exposure with ritual prevention (EX/RP). However, although effective, this treatment approach is largely inaccessible, time-consuming, labor-intensive, and expensive. A stepped-care approach to treating OCD may be more cost-effective and therefore more accessible for many individuals. Stepped-care CBT begins with the least expensive, least intrusive, most accessible option, and works up to the most expensive option if the less intrusive treatments do not work. This study will determine the benefits and cost-effectiveness of a stepped care treatment program for OCD.

Participants in this open label study will be randomly assigned to receive CBT for 6 to 14 weeks either through the stepped-care approach or immediately upon study entry. Participants will report to the study site for treatments and assessments on a regular basis, ranging from every 2 weeks to twice a week, depending on the stage of the study and the assigned treatment group. Stepped-care CBT will begin with self-administered EX/RP combined with counseling to address medication issues, life stress, and motivational enhancement. If ineffective, this treatment will be followed by therapist-administered EX/RP. OCD symptoms will be assessed at Week 6. Participants who have responded to treatment after 6 weeks will not receive further treatment. All others will continue for an additional 8 weeks. These participants' OCD symptoms will be assessed again at Week 14. Participants assigned to the stepped-care approach whose OCD symptoms improved initially, but relapsed without further treatment by the Week 14 evaluation will receive full-scale CBT. Outcomes will be assessed again at 1- and 3-month follow-up visits.

• Behavioral: Cognitive-Behavioral Therapy with EX/RP
• Behavioral: Stepped-Care CBT

• Active Comparator: Cognitive-behavioral therapy (CBT) that incorporates exposure with ritual prevention (EX/RP)
• Experimental: Stepped-care CBT

Inclusion Criteria:

• Primary diagnosis of OCD of moderate or greater severity
• Presence of OCD symptoms for at least 1 year

Exclusion Criteria:

• History of psychotic or developmental disorder
• Uncontrolled bipolar disorder
• Serious suicide risk
• Prior history of adequate CBT, including exposure and response prevention