Adolescents often show signs of physical addiction to nicotine within five months of smoking their first cigarette, Canadian researchers say.

The Canadian Press reported July 31 that researcher Jennifer O'Loughlin of McGill University studied 1,293 Montreal-area high-school students and found that "kids are reporting symptoms of nicotine addiction very, very early after onset."

In fact, signs of dependence can emerge even before young smokers begin using cigarettes on a daily or weekly basis, she said. "I think this paper really challenges the way people have been thinking about the development of nicotine dependence," said O'Loughlin. "Once cravings are experienced, the likelihood of progression to daily use and tobacco dependence is greatly increased."

O'Loughlin created a set of 12 addiction milestones for cigarette use and addiction to assess her study group, including markers like first inhalation, daily use, physical addiction, and withdrawal symptoms. "This gives a tool to practitioners ... to be able to almost diagnose where the individual is in terms of the person's trajectory towards dependence," she said.

The research is published in the Aug. 1, 2006 issue of the Canadian Medical Association Journal.