Scientists identify part of brain linked to gambling addiction

jfp40 — Tue, 08 Apr 2014 08:02:36 +0000

̽��ֱ��research, led by Dr Luke Clark from the ̽��ֱ�� of Cambridge, was published on April 7 2014 in the journal PNAS.

During gambling games, people often misperceive their chances of winning due to a number of errors of thinking called cognitive distortions. For example, ‘near-misses’ seem to encourage further play, even though they are no different from any other loss. In a random sequence like tossing a coin, a run of one event (heads) makes people think the other outcome (tails) is due next; this is known as the ‘gambler’s fallacy’.

There is increasing evidence that problem gamblers are particularly prone to these erroneous beliefs. In this study, the researchers examined the neurological basis of these beliefs in patients with injuries to different parts of the brain.

“While neuroimaging studies can tell us a great deal about the brain’s response to complex events, it’s only by studying patients with brain injury that we can see if a brain region is actually needed to perform a given task,” said Dr Clark.

For the study, the researchers gave patients with injuries to specific parts of the brain (the ventromedial prefrontal cortex, the amygdala, or the insula) two different gambling tasks: a slot machine game that delivered wins and ‘near-misses’ (like a cherry one position from the jackpot line), and a roulette game involving red or black predictions, to elicit the gambler’s fallacy. For the control groups, they also had patients with injuries to other parts of the brain as well as healthy participants undergo the gambling tasks.

All of the groups with the exception of the patients with insula damage reported a heightened motivation to play following near-misses in the slot machine game, and also fell prey to the gambler’s fallacy in the roulette game.

Clark added: “Based on these results, we believe that the insula could be hyperactive in problem gamblers, making them more susceptible to these errors of thinking. Future treatments for gambling addiction could seek to reduce this hyperactivity, either by drugs or by psychological techniques like mindfulness therapies.”

Gambling is a widespread activity: 73% of people in the UK report some gambling involvement in the past year* and around 50% play games other than the National Lottery. For a small proportion of players (around 1-5%), their gambling becomes excessive, resulting in features seen in addiction. Problem gambling is associated with both debt and family difficulties as well as other mental health problems like depression.

*2010 British Gambling Prevalence Survey

New research reveals that brain damage affecting the insula – an area with a key role in emotions – disrupts errors of thinking linked to gambling addiction.

Based on these results, we believe that the insula could be hyperactive in problem gamblers, making them more susceptible to errors of thinking.

Dr Luke Clark

John Ryan

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̽��ֱ��psychology of gambling

tdk25 — Sun, 01 Apr 2007 00:00:00 +0000

Gambling is a thriving form of entertainment in the UK, but may also become a form of addiction for some individuals. Just why do people gamble when ‘the house always wins’? Advances in brain imaging techniques are helping Cambridge scientists find out.

Gambling has been a popular source of entertainment for many centuries and across many cultures. With current changes in gambling legislation in the UK, its popularity looks set to continue. New casinos are to be established, including a large ‘super-casino’, and novel forms of gambling like internet gambling and electronic gaming machines are flourishing. Some argue these changes are a good thing: gambling is a recreational activity enjoyed by around 70% of the British public at least annually, and the gambling industry is a useful source of taxable revenue.

But all this comes at a cost – for a minority of individuals, gambling is a spiralling habit that they become unable to control. Problem (or ‘pathological’) gambling is a recognised psychiatric diagnosis present in around 1% of the population. These prevalence rates are higher in local communities around gambling facilities, and clinicians are concerned that the relaxation of British legislation will increase the incidence of problem gambling in years to come.

Against the odds

At its heart, gambling is a rather paradoxical behaviour because it is widely known that ‘the house always wins’. Whether you are gambling on fruit machines, horseracing, blackjack or roulette, the odds will have been meticulously arranged to ensure a steady profit for the casino or bookmaker. ̽��ֱ��only way to achieve this is for the gambler to make a steady loss. So why do gamblers, and particularly problem gamblers, continue to play when the overwhelming likelihood is that they will lose money?

Dr Luke Clark, in the Department of Experimental Psychology, is interested in the different ways in which gamblers over-estimate their chances of winning, including the effects of near-misses and personal choice. These features of gambling games promote an ‘illusion of control’: the belief that the gambler can exert skill over an outcome that is actually defined by chance.

Imaging the gambling brain

Recent advances in brain imaging technology are helping scientists to understand how these features of gambling games are so effective in maintaining continued play. At the Wolfson Brain Imaging Centre at Addenbrooke’s Hospital in Cambridge, Dr Clark is using functional magnetic resonance imaging (fMRI) to measure patterns of brain activity while volunteers perform a gambling game.

Previous research has shown a reliable pattern of brain activity when humans receive monetary wins. In particular, a region called the striatum, near the centre of the brain, is a crucial component in a reward circuit that also responds to natural reinforcers like food and sexual stimuli, as well as drugs of abuse like cocaine. In ongoing research, Dr Clark is measuring activity in this reward circuit as volunteers experience near-misses and choice effects during a gambling task.

Hallmarks of addiction

Both near-misses and personal choice cause gamblers to play for longer and to place larger bets. Over time, these distorted perceptions of one’s chances of winning may precipitate ‘loss chasing’, where gamblers continue to play in an effort to recoup accumulating debts. Loss chasing is one of the hallmarks of problem gambling, which actually bears much resemblance to drug addiction. Problem gamblers also experience cravings and symptoms of withdrawal when denied the opportunity to gamble.

In addition to an array of psychological factors, problem gambling may also have some important biological determinants. ̽��ֱ��brain chemical dopamine is known to play a key role in drug addiction and may also be abnormally regulated in problem gambling. Patients with Parkinson’s disease, who show degeneration of dopamine cells, can sometimes show a sudden interest in gambling, linked to their use of medications that increase dopamine transmission. Other systems in the brain are also critical, particularly the part of the frontal lobes immediately above the eye sockets, known as the orbitofrontal cortex.

Following damage to the orbitofrontal region, neurosurgical patients often show changes in their judgment and risk-taking. One patient, examined at the ̽��ֱ�� of Iowa, made a series of disastrous decisions involving extravagant business ventures and dubious personal relationships after having a tumour removed from his orbitofrontal cortex. In a collaborative study with Dr Antoine Bechara at the ̽��ֱ�� of Southern California, Dr Clark is measuring betting behaviour in a group of similar patients with damage in this region, using a simple gambling task. More subtle chemical imbalances in this brain region may accompany the transition from regular gambling to problem gambling.

Help for problem gamblers?

By further understanding the breakdown of self-control in gamblers, this programme of research carries important implications for the treatment of problem gambling, using both pharmacological and psychological therapies. Moreover, the development of objective tasks of gambling will provide more valid outcome measures for assessing the effectiveness of new treatments. By understanding how subtle features of gambling games, like near-misses and personal choice, are linked to the addictiveness of these games, future changes in gambling legislation may be in a better position to protect vulnerable individuals.

Promoting an illusion of control

Near-missesoccur when the outcome is close to the jackpot, but there is no actual win. Near-misses are common in many forms of gambling, such as when your chosen horse finishes in second place in a horserace. A moderate frequency of near-misses encourages prolonged gambling, even in student volunteers who do not gamble on a regular basis. Problem gamblers often interpret near-misses as evidence that they are mastering the game and that a win is on the way.

Personal choiceis a further determinant of illusory control, referring to situations where the gambler has some responsibility in arranging their gamble. As an example, roulette players will place higher bets if they can throw the ball onto the roulette wheel themselves, compared with if the croupier throws the ball for them. Lottery players often prefer a number sequence they have selected themselves, and may refuse to exchange their ticket for several tickets of random numbers. Choice appears to encourage a belief that the game involves skill when in fact the outcome is entirely random.

For more information, please go towww.psychol.cam.ac.uk/BCNIor contact the author Dr Luke Clarklc260@cam.ac.uk

Gambling is a thriving form of entertainment in the UK, but may also become a form of addiction for some individuals. Just why do people gamble when &lsquo;the house always wins&rsquo;? Advances in brain imaging techniques are helping Cambridge scientists find out.

Gambling games promote an ‘illusion of control’: the belief that the gambler can exert skill over an outcome that is actually defined by chance.

Dr Luke Clark

Erna from Flickr

Changing Luck for the Better

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̽��ֱ�� of Cambridge - Luke Clark

Scientists identify part of brain linked to gambling addiction

̽��ֱ��psychology of gambling

Promoting an illusion of control