Obsessive Compulsive Disorder, OCD, is a clinically recognised disorder which affects around 1-2% of the population. It is debilitating and paralysing, suffrers experience negative, repetitive and intrusive thoughts, combined with a chronic feeling of doubt or danger (obsessions). In order to quieten the anxiety, they will often repeat an action, again and again (compulsions).
Now neurosscience research by University of London, Goldsmith's, has identified the 'Precuneus', a central hub between posterior and prefrontal brain regions as a key area for intervention.  
Lee Millam talks to people with OCD and to Professor Joydeep Battacharya of Goldsmith's.