A report in this week's Nature Medicine reports the identification of a molecule that might be implicated in the pathology of obsessive-compulsive disorder (OCD).

OCD is a common psychiatric disorder defined by the presence of obsessive thoughts and repetitive compulsive actions, often in concert with anxiety and depressive symptoms. A brain region known as the striatum and its connections with the cerebral cortex have been implicated in OCD. However, the molecular bases of the disease remain unknown.

Shahin Rafii and his colleagues show that mice lacking a neuron-specific molecule termed Slitrk5 exhibit OCD-like behaviors ― excessive self-grooming and increased anxiety. These behavioural traits can be alleviated by fluoxetine, a drug commonly prescribed to treat OCD. Moreover, mice lacking Slitrk5 show overactivation of parts of the cerebral cortex and abnormalities in the striatum. In addition to identifying a new molecule involved in OCD, the mice characterized in this study may be useful as an animal model of this psychiatric condition and in investigations for new therapies.