A recent Yale study indicates that smoking impairs memory, contrary the belief of many teenage smokers who claim that tobacco heightens their ability to focus and perform in school.

Dr. Leslie Jacobsen, a professor of psychiatry and pediatrics at the Yale School of Medicine, measured the effect of smoking and smoking withdrawal on teenagers’ cognitive performance. She said that although studies have proven smoking has an adverse effect on the cognitive performance of adults, no one had previously attempted to measure its exact effect on adolescents.

“Determining the effect of smoking is even more important for adolescents than it is for adults,” said Dr. John Krystal, Jacobsen’s psychiatry colleague and collaborator on the study. “This is because tobacco and cannabis consumption can have long-term consequences in terms of performance in school, but also affect the process of brain development which occurs during adolescence.”

In her study, Jacobsen compared the cognitive performance of smokers ages 14 to 18 with that of non-smokers and individuals who had been in tobacco withdrawal for 24 hours. She said smokers’ performance was significantly lower than that of non-smokers, but those in withdrawal performed even more poorly. Jacobsen said nicotine is one of the most common drugs used by high school students, with roughly 25 percent of high school seniors smoking.

Jacobsen said the results were similar to those observed in studies with adult subjects. Confirming the highly impaired performance of smokers in withdrawal is of particular importance, Krystal said, because it explains why smokers claim tobacco consumption improves their ability to focus. He said these individuals performed below their normal levels even when they had recently smoked. Because their attention during withdrawal is even more impaired, he said they get a false impression that smoking gives them a boost.

“Smoking does not improve attention, but it creates the illusion that it does,” Krystal said.

Jacobsen said her study has several limitations. Since the subjects had not been tested before the study, it was impossible to determine exactly to what degree smoking affected them, she said. Jacobsen said she plans to further research the subject next year, and hopes to determine if the subjects’ functions will improve after an eight-week treatment program to help them quit smoking.

Despite these limitations, Jacobsen said the study has proven that once an adolescent has started smoking, quitting is an uphill battle. She said school programs discouraging smoking are the most effective way to reverse the trend of adolescent smoking.

“Prevention is very important,” she said. “We also need to realize that once an adolescent smoker has decided to quit, they absolutely need more support in school.”