The neural basis of distorted thinking in gambling addiction

Luke Clark

University of Cambridge

Gambling is a classic risky behaviour that is perhaps alarmingly prevalent: in European and 
North American household surveys, around 70% of the population report past year 
gambling, and around 80% lifetime gambling. For a minority of players, their gambling 
spirals out of control. This syndrome was first recognised as ‘compulsive gambling’, and until 
the DSM5, it was considered within the impulse control disorders. Research over the past 
decade has prompted a reconceptualisation of problem gambling within the addictions, and 
in the DSM5, ‘Disordered Gambling’ is recognised as the prototypical ‘behavioural 
addiction’. This talk will begin by highlighting some characteristics of pathological gamblers 
attending the UK National Problem Gambling Clinic, in terms of neurocognitive function, 
trait impulsivity and PET measurement of dopamine receptor binding. Despite the evident 
commonalities with drug addiction, it remains unclear how behaviours that rely on natural 
reinforcement processes can become addictive. A critical ‘added ingredient’ in gambling 
may come in the form of cognitive distortions in the processing of randomness, probability 
and skill, which occur during play. While these distortions can be elicited in the laboratory or 
brain scanner in healthy participants, there is evidence that they are enhanced in problem 
gamblers. Three distortions that I will elaborate upon are the effects of ‘near-miss’ 
outcomes, the illusion of control in chance situations, and inferring patterns in random 
sequences (the Gambler’s Fallacy). Our research work is beginning to elucidate the cognitive 
and neural mechanisms that underlie these effects.