People with an addiction have difficulty in learning when they can expect a reward: those with addiction problems process rewards in their brain differently from other people. A new research suggests this could perhaps be the reason they find it difficult to kick the habit. The new findings are published in JAMA Psychiatry.

Researchers at Radboud university medical center and Radboud University analyze brain images from previous studies in order to find out if the different in brain reward sensitivity is associated with “too much” or “too little” brain activity. Arnt Schellekens, a researcher and psychiatrist at Radboud university medical center, Guillaume Sescousse and Maartje Luijten, both from Radboud University; investigated 25 studies comprising more than 1200 individuals with and without addiction to various substances such as alcohol, cocaine and gambling.

They discovered notable difference in brain activity between expecting a reward and receiving a reward.

Individuals with substance or gambling addiction showed a weaker brain response to anticipating monetary rewards, when compared with non-addicted individuals.

According to Arnt F. Schellekens:

There was less brain activity in the striatum, a core region of the brain reward circuit, suggesting that they did not expect much from the reward.

Researchers also found a stronger response to receiving the reward in the striatum of those addicted to substance, but absent in those addicted to gambling.

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This increased response, often interpreted as increased surprise to getting the reward, could actually follow from low expectations, said Schellekens.

Researchers also say their findings may explain why the addicted are unable to decide not to use drugs or not to gamble. Additional, learning problem may lie at the basis of education.

Schellekens talked about the possibility of influencing the learning process by psychological treatment:

We want to compare the reactions to various types of rewards such as money, social rewards or drugs and also see how those reactions change over time. We are convinced that addiction treatment will benefit from a better understanding of the brain mechanisms that contribute to addiction,”

Reference: Maartje Luijten, Arnt F. Schellekens, Simone Kühn, Marise W. J. Machielse, Guillaume Sescousse. Disruption of Reward Processing in Addiction. JAMA Psychiatry, 2017; DOI: 10.1001/jamapsychiatry.2016.3084