A Primer on Obsessive-Compulsive Disorder

Editor’s note: This is the first of a two-part feature dealing with obsessive-compulsive disorder. The second part will focus on cognitive-behavioral therapy as treatment.

Obsessive-Compulsive Disorder (OCD) comes from the German word zwangsvorstellung (compelled presentation or idea), which encompasses both the mental experiences and the actions that comprise the disorder. Once thought to be rare, current lifetime and annual rates suggest that OCD is prevalent,1,2,3 and consistent across cultures and countries.4,5 

Previously classified as an anxiety disorder, OCD has now been moved into its own category along with other disorders characterized by repetitive thoughts and behaviors disorders (Body Dysmorphic Disorder [BDD], Hoarding Disorder, Trichotillomania (Hair-Pulling) Disorder, Excoriation (Skin-Picking) Disorder, and Substance/Medication-Induced Obsessive Compulsive and Related Disorder) in our new diagnostic classification systems, the DSM-5 and ICD-10.

These changes were based on studies demonstrating that these disorders, in particular OCD, BDD, and hypochondriasis, run in the same families, have a similar illness course and treatment response, and may share some biological makers. A lifetime history of chronic tic disorders and degree of insight (good, fair, poor, or absent) may now be noted under the two new specifiers in the DSM-5.

Although cutting edge advances in pharmacology, neurophysiology, neuroanatomy genetics, learning theory, and cognitive theory have contributed to a better understanding of OCD as a complex disorder caused by many etiologies, it remains one of the hardest psychological disorders to diagnose and treat. Our studies show that misdiagnosis rates are high among mental health professionals, and even higher among primary care physicians.6,7

As would be expected, taboo obsessions such as sexual and religious obsessions are more easily misdiagnosed than common obsessions such as fears of contamination or harm. Incorrect diagnoses can have disastrous consequences for patients who may be consequently referred for non-evidence based treatments or treatments intended for other conditions.

A study conducted in my research lab showed that physicians who correctly diagnosed an OCD patient vignette were more likely to recommend evidence-based treatments for OCD while those who misdiagnosed the same patient vignette with schizophrenia were more likely to recommend antipsychotic medications.8 On a more optimistic note, we found that incorporating a structured psychoeducational video intervention carefully illustrating the varied symptoms presentations substantially improved diagnosis rates among graduate trainees.7