Mental HealthPending review

Obsessive-compulsive disorder

A disorder of a hyperactive cortico-striato-thalamo-cortical 'error-detection' loop that generates intrusive doubt the mind cannot dismiss, and compulsions that relieve anxiety just enough to entrench the loop further.

In a nutshell

OCD arises from a hyperactive cortico-striato-thalamo-cortical loop that fails to switch off its own error-detection signal, generating intrusive obsessions. Compulsions relieve anxiety briefly but reinforce the loop rather than resolving it. ERP and SSRIs both retrain the same circuit and are combined in more severe illness.

Classic presentation

Recurrent intrusive thoughts about contamination or harm, recognised as excessive, accompanied by time-consuming washing or checking rituals that briefly relieve anxiety but recur, taking over an hour a day and impairing function.

Key points

  • Obsessions are ego-dystonic: the person usually recognises them as excessive or irrational, which distinguishes OCD from a delusional disorder.

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Educational content pending clinical review. Not medical advice.