*5.2. Obsessive-Compulsive Disorder*

A systematic review of 11 studies of patients with OCD found that intravenous ketamine improves obsessive-compulsive symptomatology, with rapid effects that last from days to weeks [81]. Moreover, the effects of ketamine on OCD are prolonged if augmented with cognitive behavioural therapy (CBT). In an interesting case study of a patient with treatment-resistant depression, psychosis and OCD, oral esketamine was combined with deep brain stimulation targeting the ventral anterior limb of the internal capsule, demonstrating long-term benefits over 18 months [82]. Overall, there is a requirement for more research into the use of ketamine for OCD, although there is preliminary evidence for reductions in obsessive-compulsive symptomatology.
