The psychological treatment of obsessive-compulsive disorder (OCD) with exposure and
response prevention (ERP) methods is one ofthe great success stories within the field of mental
health. Within the span of about 20 years, the prognosis for individuals with OCD has
changed from poor to very good as a result ofthe development of ERP, This success not withstanding,
the procedures are far from perfect because a substantial minority of patients still
either refiise treatment, drop out prematurely, or fail to benefit, I begin this article with a
review of the development of ERP from early animal research on avoidance learning conducted
during the 1950s, Next, I discuss the mechanisms of ERP, The bulk ofthe article
reviews the treatment-outcome literature on ERP for OCD and includes comparisons with
cognitive therapy—the "new kid on the block" with respect to psychological treatments for
OCD,
(Can J Psychiatry 2006;51:407-416)
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