A popular treatment for nicotine addiction can also cut cravings among crystal meth addicts, a US study suggests.Crystal meth – the commonly used term for methamphetamine – is a cheap and addictive drug that has become a massive problem in the US in recent years. It increases alertness and creates sensations of euphoria in users by stimulating the generation of dopamine and norepinephrine – neurotransmitters within the regions of the brain responsible for feelings of pleasure.Bupropion – the active chemical ingredient found in the nicotine addiction drug, Zyban, as well as the anti-depressant Wellbutrin – was found to reduce the drug-induced high experienced by methamphetamine users and also to lessen their urge to take the drug in response to visual cues, in a study by researchers at the University of California in Los Angeles (UCLA).Twenty methamphetamine users were given either 150 milligrams of bupropion twice a day for a week, or a placebo. Subjects were then injected with 30 milligrams of methamphetamine and asked to rate the high they experienced on a scale of 1 to 10, with 10 being the most intense imaginable. The users given doses of bupropion reported experiencing a significantly reduced high of, on average, 3 out of 10, compared to 5 out of 10 prior to the treatment. “What we found, which was unexpected, was that it significantly reduced the euphoric effect,” Thomas Newton at UCLA, who led the study, told New Scientist.