Is addiction a brain disease? Yes, if researchers are to be believed, because it changes the way the brain functions.

A team of international researchers has carried out a study and found that alcoholics and drug addicts are naturally more impulsive when compared to other normal people, The Daily Telegraph reported on Wednesday.

According to lead researcher Charlotte Boettiger of the University of North Carolina, "Their (the addicts') brains may not fully process the long-term consequences of their choices."

The researchers came to the conclusion after carrying out brain scans on nine sober recovering alcoholics.

The participants were given financial decision tasks that allowed them to choose "less money now" or "more money later". The addicts chose the "now" reward almost three times as often.

In fact, the team found that they had less activity in the orbital frontal cortex -- the part of the brain that helps people make wise long-term decisions -- than volunteers with no history of addiction.

The researchers also found a genetic link with the brain chemical dopamine -- they believe that raising dopamine levels may be a treatment for addiction.

The results of their study have been published in the 'Journal of Neuroscience'.