Kick butts for higher IQ

New York The poorer mental function seen among alcoholics, many of whom also regularly smoke cigarettes, may be partially dull in mental ability due to the long-term effects of nicotine, new research by University of Michigan's Addiction Research Center suggests.

?People who are smokers and alcoholics are at a much higher risk,? Dr Jennifer M Glass, of the University of Michigan's Addiction Research Center, said.

This finding may seem counterintuitive, since many smokers show the feeling of being more alert and focused after smoking.

Smoking also appeared to be independently associated with weaker verbal and visual-spatial reasoning, the study indicates.

Indeed, research shows that improved mental functioning is one of the immediate effects of nicotine exposure. Chronic smoking, however, is known to have the opposite effect.

Studies show that up to 87 per cent of alcoholics smoke cigarettes, compared to less than 30 per cent of the general US population.

Yet, few studies have looked into cigarette smoking as a factor that might explain the cognitive deficits reported among alcoholics.

To investigate that association, Jennifer and her colleagues examined brain function among 172 men from the same community, including 103 men who use alcohol.

The team found that men with higher scores on the lifetime alcohol problems scale (LAPS) and those who reported a higher number of pack-years of smoking (packs of cigarettes smoked per day times number of years) both had lower IQ scores and lower scores on a test of global proficiency.

The proficiency test took into account the speed and accuracy with which the men were able to perform on a battery of tests including those that measured short-term memory, verbal reasoning and mathematical reasoning.

Upon further investigation, the researchers found that smoking predicted poorer global proficiency even more strongly than alcoholism did.

Their findings were published online before publication in Drug and Alcohol Dependence.

Though smoking did not account for all of the decreased neurocognitive functioning observed among the alcohol abusers, it did seem to account for some of the effects, the report indicated.

Based on the current report, Jennifer said, "If you need another reason to quit smoking, it's a good potential one to add to the list."

(Source: Drug and Alcohol Dependence, 2005)