February 1, 2012

expert reaction to research into addiction vulnerability and the brain, as published in Science

A paper in the journal Science into the subtleties of cause and effect in brain abnormalities and addiction.

David Branford, Chief Pharmacist for Derbyshire Mental Health Trust, said:

“The paper indicates that there is more to stimulant addiction than genetic predisposition or a more impulsive nature. This study prompts to look outside of these factors and to consider social and environmental factors as well. This study also implies that addiction does not produce noticeable changes to brain structure and function which means that there may be provision for looking at new treatment techniques for addiction.”

Dr Paul Keedwell, Consultant Psychiatrist, Cardiff University, said:

“Addiction, like most psychiatric disorders, is the product of nature and nurture. This interesting study of sibling pairs suggests that an inherited inability to direct behaviour toward long term goals, and related brain ‘abnormalities’, represent risk factors for addiction. However, we need to follow up people over time to quantify the relative risk of nature versus nurture. If we could get a handle on what makes unaffected relatives of addicts so resilient we might be able to prevent a lot of addiction from taking hold”

Derek Hill, Professor of Medical Imaging Science at UCL and CEO of IXICO, said:

“This cleverly designed research uses brain scanning to compare the brains of drug-addicts, normal non-addicts, and non-addicts who are siblings of the addicts. They uncover evidence of certain structures in the brain associated with self-control. The exciting consequence of this finding is that this sort of brain scanning might be used as a “biomarker” to help develop new treatments for impaired self-control: not only for drug addiction, but perhaps also for other conditions including over-eating. Unfortunately, it takes years to develop an imaging method like this to the level of maturity needed to help develop new treatments, so practical benefits are some way in the future.”

Professor Les Iversen, Department of Pharmacology, University of Oxford, said:

“A former Director of the US National Institute on Drug Abuse, Alan Leshner, defined addiction as “a chronic, relapsing brain disorder”, and since then evidence has accumulated to support this view.

“The current Director of NIDA, Dr Nora Volkow has reviewed the latest findings from Ersche and colleagues, describing alterations in brain regions which may underlie the propensity to become addicted. These findings partly answer the questions posed by Dr Volkow: Does chronic drug abuse cause brain abnormalities, or do they develop before the onset of dependence?

The findings from the Cambridge group show that both answers may be true. Addicted subjects and their siblings showed differences in brain regions associated with impulsivity, i.e. these appear genetically determined.

“But, in addition, there were further subtle differences in brain structure between the addicted and non-addicted siblings, whose cause remains obscure. The review by Volkow and Bayler skilfully merges these new data on brain anatomy, with work from her group that has helped to define the molecular changes in brain chemistry that occur in addiction.

“These new findings reinforce the view that the propensity to addiction is dependent on inherited differences in brain circuitry, and offer the possibility of new ways of treating high-risk individuals to develop better “self control”.”

‘Abnormal Brain Structure Implicated in Stimulant Drug Addiction’ by Ersche, K.D. et al. published in Science on Thursday 2nd February.
An accompanying ‘Perspectives’ article, ‘To Stop Or Not to Stop’ by Volkow, N.D. et al., is published in the same issue.