Obsessive-compulsive disorder (OCD) is a debilitating condition that affects 2-3% of the population at some point in life. Patients suffer from recurrent intrusive thoughts (obsessions) that are distressing and hard to get rid of such as fears of contamination or that something horrible will happen to a loved one. Sufferers then engage in repetitive rituals designed to neutralise these thoughts (compulsions) including obsessive hand-washing and checking. Scientists at Cambridge University attempted to find out which parts of the brain are affected in OCD. They studied 40 people, 14 of them were healthy and had no family history of OCD, 14 had OCD and 12 were immediate relatives of OCD patients. They gave the participants a learning task and monitored their brains using functional magnetic resonance imaging (fMRI). The OCD participants and their family members all showed under-activation in an area of the brain called the lateral orbital frontal cortex which is involved in decision making and behaviour.
You can find out more about this research at