Creatures of habit: Disorders of compulsivity share common pattern and brain structure

Person washing hands (cropped image). Credit: Dave 77459

People affected by binge eating, substance abuse and obsessive compulsive disorder all share a common pattern of decision making and similarities in brain structure, according to new research from the University of Cambridge.

In a study published in the journal Molecular Psychiatry and primarily funded by the Wellcome Trust, researchers show that people who are affected by disorders of compulsivity have lower grey matter volumes (in other words, fewer nerve cells) in the brain regions involved in keeping track of goals and rewards.

In our daily lives, we make decisions based either on habit or aimed at achieving a specific goal. For example, when driving home from work, we tend to follow habitual choices – our 'autopilot' mode – as we know the route well; however, if we move to a nearby street, we will initially follow a 'goal-directed' choice to find our way home – unless we slip into autopilot and revert to driving back to our old home. However, we cannot always control the process and make repeat choices even when we know they are bad for us – in many cases this will be relatively benign, such as being tempted by a cake whilst slimming, but extreme cases it can lead to disorders of compulsivity.

In order to understand what happens when our decision-making processes malfunction, a team of researchers led by the Department of Psychiatry at the University of Cambridge compared almost 150 individuals with disorders including methamphetamine dependence, obesity with and , comparing them with of the same age and gender.

Study participants first took part in a computerised task to test their ability to make choices aimed a receiving a reward over and above making compulsive choices. In a second study, the researchers compared brain scans taken using (MRI) in healthy individuals and a subset of obese individuals with or without (a subtype of obesity in which the person binge eats large amounts of food rapidly).

The researchers demonstrated that all of the disorders were connected by a shift away from goal-directed behaviours towards automatic habitual choices. The MRI scans showed that obese subjects with binge eating disorder have lower grey matter volumes – a measure of the number of neurons – in the orbitofrontal cortex and striatum of the brain compared to those who do not binge eat; these are involved in keeping track of goals and rewards. Even in healthy volunteers, lower volumes were associated with a shift towards more habitual choices.

Dr Valerie Voon, principal investigator of the study, says: "Seemingly diverse choices – drug taking, eating quickly despite weight gain, and compulsive cleaning or checking – have an underlying common thread: rather that a person making a choice based on what they think will happen, their choice is automatic or habitual.

"Compulsive disorders can have a profoundly disabling effect of individuals. Now that we know what is going wrong with their decision making, we can look at developing treatments, for example using psychotherapy focused on forward planning or interventions such as medication which target the shift towards habitual choices."

More information: Voon, V et al. Disorders of compulsivity: a common bias towards learning habits. Molecular Psychiatry; E-pub 20 May 2014

add to favorites email to friend print save as pdf

Related Stories

Researchers ID a brain mechanism that weighs decisions

Feb 05, 2014

We tend to be creatures of habit. In fact, the human brain has a learning system that is devoted to guiding us through routine, or habitual, behaviors. At the same time, the brain has a separate goal-directed ...

Recommended for you

Molecular basis of age-related memory loss explained

2 hours ago

From telephone numbers to foreign vocabulary, our brains hold a seemingly endless supply of information. However, as we are getting older, our ability to learn and remember new things declines. A team of ...

The neurochemistry of addiction

3 hours ago

We've all heard the term "addictive personality," and many of us know individuals who are consistently more likely to take the extra drink or pill that puts them over the edge. But the specific balance of ...

Study examines blood markers, survival in patients with ALS

19 hours ago

The blood biomarkers serum albumin and creatinine appear to be associated with survival in patients with amyotrophic lateral sclerosis (ALS) and may help define prognosis in patients after they are diagnosed with the fatal ...

User comments