Comparison of Effects Between Conventional Dose and High Dose Escitalopram on Clinical Improvement in Patients With Obsessive-compulsive Disorder

Inclusion criteria

• Man or woman, aged 18 to 65 years, outpatient
• Primary OCD patients diagnosed with DSM-IV-TR, having OCD symptoms for more than six months
• Severity: Y-BOCS score of >= 20 at screening and baseline
• No history or evidences of clinically significant physical problem, or abnormal laboratory findings at screening
• Drug free period of at least 2 weeks before study drug administration (in case of fluoxetine, at least 5 weeks). However, allowed medications in this study could be taken even before study drug administration.

Exclusion criteria

• primary active DSM-IV axis I diagnosis other than OCD
• History of substance, including alcohol, dependence and psychotic symptoms
• Current depression A. Risk of suicidal attempt B. 20-item Hamilton Depression Rating Scale (HAM-D)(exclude 21th item, obsession) of >17 at screening or baseline
• Drug allergy A. Known or suspected hypersensitivity to escitalopram or citalopram B. History of severe drug allergic reactions or hypersensitivity
• History of no response to escitalopram or citalopram treatment
• History of electroconvulsive therapy or received an injectable antipsychotic formulation within 6 months before screening
• Women who are pregnant, planning to become pregnant, or breast-feeding
• Ongoing cognitive behavior therapy (CBT) of OCD
• Hoarding or collecting type
• Unable to perform study protocol as clinically assessed by the investigator (ex, severe personality disorder)