When people talk about obsessive–compulsive disorder (OCD), they usually picture someone scrubbing their hands raw, or checking a lock over and over again. That image is not wrong, but it’s incomplete. OCD has a far richer, more complex clinical picture—and recent revisions in psychiatric classification systems have tried to capture this reality.

The World Health Organization’s ICD-11 (International Classification of Diseases, 11th edition) has taken a bold step forward in redefining OCD. These updates come after decades of research showing that the older criteria (ICD-10, from 1990) missed important aspects of the condition.

Why the Update Was Needed

ICD-10 defined obsessions as “ideas, images, or impulses” intruding into the mind again and again. Compulsions were “stereotyped behaviors” repeated endlessly. That framework captured the basics, but it left important clinical realities out:

• Many patients experience sensory phenomena—physical urges, just-right sensations, or feelings of incompleteness—that drive their compulsions.

• Mental compulsions (like silent prayers, counting, or mental reviewing) are just as common as handwashing or checking, yet were absent from ICD-10.

• Insight varies widely: some patients know their fears are irrational, others are partially convinced, and a small group believe them entirely. ICD-10 didn’t account for this spectrum.

Large international studies, including a Brazilian multicenter cohort of over 1000 patients, confirmed these gaps. For example, more than 56% had mental compulsions, and nearly 60% reported sensory phenomena, regardless of whether they also had tic disorders.

What ICD-11 Does Differently

The new system reflects these realities:

• Obsessions are now described as ideas, images, or urges (not “impulses,” which overlaps with impulse-control disorders).

• Compulsions include both overt behaviors and covert mental acts.

• Insight specifiers are added, ranging from excellent to absent, to avoid misdiagnosis with psychotic disorders.

• The emphasis is on dimensionality—understanding OCD across symptom domains (contamination, symmetry, aggression, sexual/religious, hoarding, miscellaneous) rather than squeezing cases into rigid categories.

Why It Matters for Clinicians and Patients

This shift isn’t just academic. It changes how OCD is recognized and treated:

• A patient stuck in endless mental rituals will now fit the diagnosis more clearly.

• Sensory experiences like “just-right” feelings are acknowledged as legitimate drivers of compulsions, not quirks to be overlooked.

• Clinicians are reminded to probe insight carefully—poor insight may predict more severe illness and lower engagement with therapy.

In short, ICD-11 pushes us to look beyond stereotypes and capture the lived phenomenology of OCD. It brings diagnosis closer to what patients actually experience, and that can only improve care.

Coming Next in the Series

In the next article, we’ll dive deeper into one of the most fascinating aspects of OCD: sensory phenomena—the invisible urges and feelings that drive compulsions.

About the Author

I’m Dr. Srinivas Rajkumar T, MD (AIIMS, New Delhi), Consultant Psychiatrist based in Chennai. Through my clinical practice and writing, I aim to make psychiatry more understandable and less intimidating.

📍 Mind and Memory Clinic, Apollo Clinic, Velachery, Chennai (Opp. Phoenix Mall)
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