Binge eating, obsessive compulsive disorder (OCD), and even methamphetamine addiction may all be influenced by how the brain functions - namely how much grey matter is found in "goal-oriented" parts of the brain, according to a recent study.

The study, published in Molecular Psychiatry, details how people who tend to make compulsory decisions - which are often harmful - all happen to exhibit the same brain patterns and physiological evidence.

"Seemingly diverse choices - drug taking, eating quickly despite weight gain, and compulsive cleaning or checking - have an underlying common thread," principle researcher Valerie Voon said in a recent statement. "Rather that a person making a choice based on what they think will happen, their choice is automatic or habitual."

Voon explained that habitual habits can all have the same underlying casual factors, despite how differently they may be presented in everyday life.

According to the study, one such factor Voon's team quickly discovered was low gray matter volumes in the orbitofrontal cortex and striatum of the brain - regions that keep a mind goal and reward oriented.

This was determined after Voon and his team compared nearly 150 people with compulsion disorders to a group of healthy participants of the same age and gender.

These participants were first asked to carry out simple tasks on a computer that were designed to measure their ability to make goal-oriented decisions, and their tendency to slip into automatic and habitual action.

Magnetic resonance images (MRIs) were also taken of the brains of theses participants, to see if any physiological patterns in the brain were shared among the compulsive participants that were not shared among the healthy group.

According o the sturdy, resulting data showed that the compulsive group was consistently worse at making goal-oriented decisions. Likewise their brains showed notably less gray matter - a sign of less brain cells - in goal-focused parts of the brain, compared to the healthy group.

According to Voon, identifying this physiological factor is an important step towards helping people suffering from compulsive disorders.

"Now that we know what is going wrong with their decision making, we can look at developing treatments... or interventions such as medication which target the shift towards habitual choices."

The study was published in Molecular Psychiatry on May 20.