NewScientist (11 March 2017) reports on the latest theory for OCD:
THE thoughts and urges that are characteristic of obsessive compulsive disorder (OCD) may be caused by an inability to distinguish between safe and risky situations.
People with OCD feel they have to carry out certain actions, such as washing their hands again and again, or repeatedly checking the oven has been turned off. Those worst affected may spend hours every day on these compulsive “rituals”.
To find out more about why this happens, Naomi Fineberg of the Hertfordshire Partnership University NHS Foundation Trust in the UK and her team trained 78 people to fear a picture of an angry face. They did this by sometimes giving the volunteers an electric shock when they saw the picture. About half the group had OCD.
The team then tried to “detrain” the volunteers, by showing them the same picture many times, but without any shocks. Judging by how much the volunteers sweated when they saw the picture, the team found that people without OCD soon learned to stop associating the face with the shock, but people with the condition remained scared.
Brain scans revealed that the people with OCD had less activity in their ventromedial prefrontal cortex, a brain area involved in signalling safety and predicting rewards (PNAS, DOI: 10.1073/pnas.1609194114).
Suggesting an organic problem susceptible to medical treatment. It has the virtue of being believable.
