Diagnostic criteria for obsessive-compulsive disorder (OCD) — common mistakes

When describing the diagnosis of OCD, always explicitly link the symptoms to 'clinically significant distress or impairment in functioning'. Examiners look for your understanding that it is the negative impact on a person's life, not just the presence of symptoms, that defines the disorder.

This is a common misconception that trivialises the disorder. While many people have preferences for order, clinical OCD is defined by its severity. The diagnostic criteria (DSM-5) state that the obsessions or compulsions must be time-consuming (over an hour a day) and/or cause significant distress and impairment in a person's ability to function at work, school, or in social relationships. A preference for tidiness does not meet this clinical threshold.

No. The primary diagnostic criterion (Criterion A in DSM-5) states that the person must have obsessions, compulsions, or both. While it is most common for individuals to experience both (with compulsions being performed to alleviate the anxiety from obsessions), it is possible to be diagnosed with a presentation that is predominantly obsessional or predominantly compulsive. However, a purely obsessional presentation without any mental compulsions is considered rare.

This is a key distinction. In OCD, compulsions are performed to reduce anxiety or distress, not for pleasure. The individual feels 'driven' to perform them and often finds them to be excessive or irrational. The relief felt is from the reduction of anxiety, which is a negative reinforcement loop. Behaviours that are inherently pleasurable or comforting, such as a hobby or a soothing repetitive action (sometimes seen in autism spectrum disorder), are not considered compulsions in the context of an OCD diagnosis.