Predicting Relapse in Treatment-Seeking Pathological Gamblers using Impulsivity and Compulsivity Assays

Gambling is a widespread behaviour that around 70% of the British population engage in at least occasionally. In some individuals, gambling spirals out of control and takes on the features of an addiction. Research into the causes of drug addiction in humans is hampered by the fact that the drugs themselves often have a damaging effect on the brain, so that it is very difficult to separate the causes from the consequences of the addiction. As a ?behavioural addiction? where no drug is consumed, problem gambling may offer some important insights into the mechanisms by which all addictions develop. The current proposal is concerned with ?pathological gambling?, the most severe form of the disorder, and we will recruit a large group of these subjects as they begin a treatment program at a specialist NHS clinic in London. Little is known about the psychological make-up of pathological gamblers in the UK, because few treatment facilities were available until recently. We will compare pathological gamblers (n=100) against healthy non-gamblers (n=50) on questionnaire measures and a computerised assessment of impulsivity (the tendency to make quick or unplanned actions) and compulsivity (the tendency to repeat an action when it is no longer productive). These psychological constructs are central to recent theories of addiction. We expect that around half our gamblers will also be addicted to either alcohol, nicotine or illicit drugs, and we will compare gamblers with and without substance addictions on the psychological assessment. We will monitor how the gamblers? symptoms improve with treatment, at a 12- and 24- week follow-up, in order to test whether psychological function at the beginning of treatment can be used to predict which gamblers will respond best. Finally, we will recruit 6 gamblers and 6 non-gamblers for a brain scan using a radioactivity-labelled dopamine drug, in order to measure levels of dopamine function in the gamblers. Changes in dopamine function are a robust finding in the substance addictions, but have not been examined in the behavioural addictions. The brain imaging data will constitute a feasibility pilot study for a larger funding bid to look at brain chemistry in problem gambling.

Pathological gambling (PG) is a putative ?behavioural addiction? where a healthy and legal activity becomes dysfunctional, characterised by a pre-occupation with gambling, repeated attempts to reduce or quit gambling, and consequent functional impairment (e.g. relationships, debt, employment). Very little is known about the characteristics of treatment-seeking PG individuals in the UK, given that few treatment facilities existed until recently. The substantial cultural variability in gambling means that it is vital to corroborate international data at a national level. More broadly, research into PG also has the potential to provide key insights into vulnerability mechanisms and aetiological processes across the addictions, in brains that are not confounded by the damaging effects of chronic drug consumption. This 2-year proof-of-concept application aims to characterise the neurocognitive profile associated with PG, in treatment-seeking individuals attending the newly-established CNWL National Problem Gambling Clinic. We will compare 100 PG subjects against 50 healthy non-gamblers on a research assessment comprising clinical scales, psychometric questionnaires, and computerised neurocognitive tests that converge on the twin constructs of impulsivity and compulsivity, which are central to current theoretical models of addiction. By testing a large and clinically-representative sample, we will be able to compare PG individuals with and without co-existing substance use problems including nicotine and alcohol dependence. We will test PG subjects within two weeks of initiating a cognitive-behavioural treatment program, and we will monitor treatment response at 12- and 24- weeks to examine whether impulsivity and compulsivity measures predict which patients meet short-term treatment objectives. Finally, we will recruit a small group of PG subjects (n=6) and non-gambling controls (n=6) for a Positron Emission Tomography scan using the dopamine radioligand [18F]fallypride, in order to directly measure central dopamine neurotransmission in a behavioural addiction for the first time. Changes in dopamine function are a robust finding in substance addiction, and may underpin the impulsivity and compulsive features that are thought to characterise these disorders. The PET feasibility data will form the basis for larger funding bids to elucidate the neurochemical basis of PG.