A paper published by Obesity Reviews compares neurological responses to reward in participants with obesity, substance addiction and non substance (or behavioural addiction, such as gambling.) It is the first objective integration of fMRI (functional magnetic resonance imaging) results on studies in these areas.

The paper compares previous studies on neurological responses to stimuli (such as food or drug-related images.) The results show that those with substance addictions and obesity both had increased activity in the part of the brain responsible for emotional processing, fear and anxiety (the right amygdala) and the part associated with the rewarding effects of drugs of abuse, food and sexual behaviour (the left accumbens) in response to stimuli.

Although the neurological similarities between substance addiction and obesity are comparatively small, they are located in areas of the brain crucial for the processing of reward and salience (how much an item stands out.)

One explanation for the similarities is that the enhanced focus on rewarding stimuli may be associated with the presence of some compulsive-like behaviour or with some degree of difficulties in impulse control. The authors argue thatovereating may be better described as a continuum with an increasing degree of compulsive eating behaviour, than as an addiction.

It is hoped that the paper's findings will help inform treatment of obese patients and help them to achieve more efficient impulse control behaviour.