According to a study of over 20,000 Israeli military recruits, it is found that young men who smoked a pack of cigarettes a day or more had IQ scores 7.5 points lower than non-smokers. "Adolescents with poorer IQ scores might be targeted for programmes designed to prevent smoking," said Dr Mark Weiser and colleagues from Sheba Medical Center in Tel Hashomer, who did the study. The researchers looked at 2,0211 men who were 18-year-old and recruited into the Israeli military. The group did not include anyone who was having major mental health problems.
According to the study, the average IQ for non-smokers was about 101, while it was 94 for men who had started smoking before entering the military. The IQ steadily dropped as the number of cigarettes smoked increased, from 98 for people who smoked one to five cigarettes daily to 90 for those who smoked more than a pack a day. IQ scores from 84 to 116 are considered as the average intelligence.