OCD: better understanding needed to guide treatment

A review of obsessive-compulsive disorder (OCD) published in The Lancet has highlighted the heterogeneity of the illness, emphasised the lack of understanding of its causes, and questioned whether it should continue to be regarded primarily as an anxiety disorder. Biological models proposed that anomalies in serotonin pathways and dysfunctional pathways in the orbito-striatal area and dorsolateral prefrontal cortex were central to the pathology. This hypothesis helped explain the efficacy of SSRI antidepressants in its treatment, the review said. An alternative cognitive-behavioural model had some empirical support but did not fully explain the symptoms, the review noted. It emphasised the importance of dysfunctional beliefs, which could be addressed by CBT and exposure therapy. New research proposed that NMDA glutamate receptors were important for expressing the conditioned fear responses that could occur in OCD, the review authors wrote. D-cycloserine, used in humans for many years to treat tuberculosis, was also an NMDA agonist and preliminary studies had shown it might be helpful in controlling such responses, they said. There was debate about how OCD should be reflected in DSM-V. Some authorities thought it should be included in a new category of obsessive-compulsive-related disorders that would also include Tourette’s syndrome, grooming disorders like trichotillomania, body dysmorphic disorder and eating disorders. Lancet 2009; 374: 491-499....