July 13, 2005
Odds of recovery
The pharmaceutical industry has long gambled with the law of unintended consequences—think about those dire warnings of four-hour erections. But this is in an altogether different league:
Patients treated with drugs for Parkinson’s disease can turn into compulsive gamblers, a study suggests. Doctors in America treated 11 patients who had a change of personality when prescribed drugs that mimic the behaviour of the mood chemical dopamine.
One of them was a clergyman who said that he had become obsessed with gambling, and a woman patient lost $100,000 (£57,600) and broke up her marriage as a result of the same obsession. She could not drive past a casino without going in. Other patients lost as much as $200,000 in six months. When the drugs were withdrawn the gambling habit disappeared.
… Parkinson’s patients have reduced levels of dopamine, which relays messages between brain cells. It is this that causes the symptoms of muscle rigidity and tremor. But dopamine is also known to play a role in helping the brain to recognise and seek sources of pleasure — the basis of addiction.
The patients involved had, at most, only occasionally gambled for fun in the past. But clinic visits revealed that their personalities went through a dramatic change after starting to take the drugs. In seven cases pathological gambling developed within three months of increasing the medication dose or reaching its “maintenance” level. The four other patients became compulsive gamblers after 12 to 30 months.
The study identified one drug, pramipexole, as the most likely to trigger compulsive gambling—but only in about 1.5% of patients. More at the Archives of Neurology.
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