Adolescents with extreme reward sensitivity who focus more attention on addictive substances in a computer experiment appear to be at greater risk of developing substance abuse. Existing addiction treatments could be supplemented by a computer exercise that retrains automatic processes in the brain. This is the conclusion of Madelon van Hemel in her thesis, which she will defend at the University of Groningen on 10 December.
What makes adolescents more susceptible to substance abuse and which cognitive processes are at the root of this? These questions were the starting point of Van Hemel’s research, for which she carried out various experimental studies.
Van Hemel first looked for a possible relationship between reward sensitivity and substance use in adolescents. ‘I wanted to find out if an increased urge to use alcohol and drugs might start with an increased urge for reward, because addictive substances work on the reward system in the brain.’ She asked 750 adolescents around the age of 16 to carry out a computer task in which they were asked to react to images that could predict a possible reward. Those adolescents who had a higher intake of alcohol, tobacco and cannabis reacted faster to images that predicted a greater chance of reward: their attention was automatically drawn to these images. This is what is known as automatic attention to reward stimuli and it proved to predict the extent of hard drugs use among the adolescents in the study. In another study in which a questionnaire was used to measure reward sensitivity, extremely reward-sensitive adolescents were found to drink more alcohol. ‘So reward sensitivity does seem to play a role in the development of substance use’, says Van Hemel.
Van Hemel then studied the role of automatic attention in alcohol and drug use. ‘We saw that adolescents who automatically allowed their attention to “linger” on images of alcohol on the computer had a higher alcohol intake. This was particularly the case with adolescents who found it difficult to control their attention.’ Adolescents who had undergone addiction treatment had very strong automatic attention (‘attention bias’) to the substance to which they were addicted and this was in relation to the severity of the addiction. Automatic attention was strong in adolescents with both relatively strong and weak attentional control. Van Hemel: ‘It may be that at the start of substance use conscious control can be used to control its intake, but that with abuse the automatic processes have already become so strong that conscious control can simply no longer keep it in check.’
Six months after the adolescents began addiction treatment there had been no significant reduction in their intake, the severity of the addiction nor their automatic attention. On the basis of her research Van Hemel can see opportunities to supplement existing treatments. ‘Regular treatments generally concentrate on behavioural change, while the automatic processes – which you therefore have no conscious influence on – actually seem to play a greater role. Treatments could possibly be supplemented by a computer exercise that aims to retrain these automatic processes in the brain.’
Madelon van Hemel conducted her PhD research, which was funded by ZonMW, at the Department of Clinical Psychology at the Faculty of Behavioural and Social Sciences. The title of the thesis is Can’t take my eyes off of you. The role of cognitive biases, reward sensitivity and executive control in adolescent substance use and abuse. Van Hemel is currently senior researcher at Verslavingszorg Noord Nederland (VNN), an organization that helps treat addiction.
Prof. Hedderik van Rijn explains his research into the perception of time in a video lecture (in Dutch) by the Universiteit van Nederland.