It is well known that a high proportion of people with schizophrenia are heavy smokers, but why should this be so? According to researchers from Toronto, the answer might be straightforward — they derive more pleasure from nicotine than the average individual.

The key is not in the schizophrenia itself, but in the dopamine-blocking drugs that are often used to treat the condition. It was previously thought that dopamine enhanced the rewarding effects of nicotine, by stimulating the ventral tegmental area (VTA). However, team leader Steve Laviolette found that the VTA is also responsible for aversion to nicotine, and that “blocking dopamine blocked the adverse effects of nicotine, but ramped up the rewarding sensations induced by the drug” (Canadian Press, 13 February 2003).

Investigations into α7 nicotinic receptor function, by a team in Colorado, provide evidence that smoking might even help to relieve some of the distressing symptoms of schizophrenia: “When most people hear a clock tick or a bird chirp, their brains can filter out the sounds after the first few ticks or chirps. But schizophrenics hear each of those ticks and chirps as equally loud and intrusive. Smoking heavily appears to lower these sounds a bit” (Rocky Mountain News, USA, 14 February).

But do the costs outweigh the benefits? Laviolette says “It's a two-edged sword. The drug is removing the psychosis but at the same time making them addicted to ... extremely dangerous drugs” (Canadian Press). However, the Colorado team leader Cathy Adams points out that “understanding the delicate balance between the nicotinic receptor and other chemicals in the brain could lead to a medication far more effective and healthy than tobacco” (Rocky Mountain News).