Traumatic childhood may increase the risk of drug addiction

Led by Dr Karen Ersche, the Cambridge researchers aimed to identify risk factors that make a person vulnerable to developing drug dependence. They examined 50 adults with cocaine dependence together with their biological brothers and sisters who have never abused drugs. All participants underwent extensive assessments of their personalities, including their ways of feeling and thinking. The researchers were also interested in negative experiences that participants may have had during childhood (to include physical, emotional or sexual abuse).

Dr Ersche, of the Behavioural and Clinical Neuroscience Institute (BCNI) at the University of Cambridge, said: "It has long been known that abusive experiences during childhood have long-lasting effects on behaviour in adulthood and this was confirmed by our results. The siblings had more troubled childhoods compared to healthy peers in the community, and we also found a direct relationship between traumatic childhoods and their personalities."

She added: "This relationship is interesting because impulsive personality traits are known to increase the risk of becoming addicted to drugs but it is not an excuse for drug-taking."

The childhoods of the brothers and sisters of the cocaine-dependent individuals were also traumatic, and they also exhibited higher-than-normal levels of impulsive and compulsive behaviours, but they did not abuse drugs.

The researchers next intend to explore how the siblings who do not abuse drugs managed to deal with their traumatic childhoods and their highly impulsive and compulsive personalities. The scientists want to understand what makes the siblings resilient against addiction. A better understanding of what protected the brothers and sisters from drug abuse may provide vital clues for developing more effective therapeutic interventions for those trying to beat their addiction.

Dr Ersche added: "Not all individuals with these personality traits would have had a traumatic upbringing. Nor does everyone with these traits develop an addiction. However, our findings show that some people are particularly at risk and their upbringing may have contributed to it."

The study was funded by the Medical Research Council and conducted within the Behavioural and Clinical Neuroscience Institute at the University of Cambridge, which is co-funded by the MRC and the Wellcome Trust.