THURSDAY, May 11, 2006 (HealthDay News) -- Even watching someone smoke may be harmful, a new study suggests.
When smokers anticipate having a cigarette in the near future, their brains are affected more by external clues -- such seeing someone else smoke -- than by their level of craving or how long they've gone without a cigarette, a new study finds.
Canadian researchers used functional magnetic resonance imaging (fMRI) to scan the brains of 20 smokers who were divided into two groups: expectant (they could smoke immediately after the test), and non-expectant (they could smoke only four hours after the test).
While their brains were being scanned, the study participants were shown videotapes of people lighting cigarettes, smoking while socializing, or blowing smoke rings.
In smokers who anticipated having a cigarette immediately after the test, these videos activated areas of the brain associated with arousal, attention, and cognitive control. In contrast, smokers who had to wait four hours to have a cigarette showed almost no brain response to the visual smoking cues, even if their craving to smoke was a strong as the expectant smokers.
"Although the effect of exposure to drug-associated clues has been studied with various drugs of abuse, this is the first study to show the link between expectancy levels and smoking cues," Dr. Alain Dagher, a neurologist at the Montreal Neurological Institute and the department of psychology at McGill University, said in a prepared statement.
"Our findings confirm the importance of expectancy in the neural response to these cues and lend support to the theory that these cues act on brain areas involved in arousal and attention, particularly the dorsolateral prefrontal cortex, which is involved in the regulation and planning of drug-seeking or drug-avoiding behavior," Dagher said.
The study appears in the current issue of Neuropsychopharmacology.
More information
The U.S. National Institute on Drug Abuse has more about nicotine addiction.
