The purpose of this research study is to evaluate whether Exposure and Response Prevention Therapy (ERP) can help adults with obsessive-compulsive disorder (OCD) in China following a training of professionals and ongoing consultation.

The purpose of this research study is to evaluate whether Exposure and Response Prevention Therapy (ERP) can help adults with obsessive-compulsive disorder (OCD) in China following a training of professionals and ongoing consultation.The treatment time for each participant is approximately 12 weeks. This includes the time between the referral and the beginning of treatment, the treatment sessions, and the 1-month follow-up time. Therapy sessions will take place twice per week for 15 sessions total and last about 90 minutes each. In addition to the therapy sessions, participants will have 3 separate assessments. These assessments will occur (1) right after they agree to participate in the study, (2) immediately after ERP ends, and (3) 1 month after ERP ends. The assessments will take about 1 ½ hours each.

Inclusion Criteria:

• Minimum score of >16 on the Y-BOCS; this score indicates clinically significant OCD symptom severity;
• Medically healthy
• Outpatient men and women age 18 years and older;
• Meets DSM-IV criteria for a diagnosis of OCD as determined by the MINI. OCD is the primary psychiatric diagnosis (i.e., it is defined by the patient as the most important source of current distress);
• Able to communicate meaningfully with the investigators and competent to provide written informed consent. IQ estimate > 85 standard score.

Exclusion Criteria:

• Current clinically significant suicidality or individuals who have engaged in suicidal behaviors within the past 12 months will be excluded and referred for appropriate clinical intervention;
• Presence of any clinical features requiring a higher level of care (inpatient or partial hospital treatment);
• Current or past DSM-IV bipolar disorder (Current or past unipolar depression is not an exclusion criterion. We will allow comorbid depression, to ensure that we are treating a representative OCD sample. Depression is the most common complication in OCD, and about one third of the OCD clinical samples are depressed.)
• Schizophrenia, schizoaffective disorder, or any other current or lifetime DSM-IV psychotic disorder;
• Current or recent (within 3 months of study entry) DSM-V alcohol or drug dependence or abuse (other than nicotine), or a positive urine drug screen for any illicit substances of abuse;
• Estimated IQ <85 on the WASI, mental retardation, dementia, brain damage, or other cognitive impairment that would interfere with the capacity to participate in the study and complete self-report measures;
• Any medical conditions that might contraindicate use of the study treatments, as determined by medical physical and laboratory tests by the study physicians;
• Presence of any significant and/or unstable medical illness which might lead to hospitalization during the study duration; subjects with a stable medical condition may participate with the agreement of the subject's physician and the study physician who performs the study physical exam;
• Concurrent psychotherapy of any type (e.g., CBT/ERP, supportive, psychodynamic) and duration;
• History of adequately-delivered exposure-based cognitive-behavioral therapy (i.e., 10 or more sessions of specific and regular exposure and/or response prevention assignments; as needed and with patients' written permission we will confer with prior treatment providers).