More than half of young smokers in Northern Ireland start the habit before they turn 13, it emerged today.
Smoking was also found to be more common among secondary school girls than boys.
Dr Amanda Amos warned pre-teens and teenagers had a misguided conception about cigarettes.
The Edinburgh University academic said: "A young person's understanding of smoking is very different to that of an adult's in that they think they are in control of the situation and can quit at any point.
"They do not see themselves as smokers, they will say they are just a 'social smoker' and believe they can give it up at a time of their choosing in the future but the fact is that smoking is already controlling them by this stage.
"We know that young people who want to give up find it difficult to do so."
Dr Amos, who will address a seminar in Antrim tomorrow, claimed services to enable adults to quit would be unlikely to meet the requirements of young smokers.
Victoria Creasy, Senior Manager for Alcohol, Drugs and Tobacco at the HPA, said the vast majority of young people in the province were aware of the link between smoking and lung cancer But she said around half of those surveyed felt the habit could help them make friends more easily, while smokers aged 12-13 were four times more likely to have siblings who smoked.
Ms Creasy added: "Of the people in Northern Ireland who set a quit date through smoking cessation services last year, those aged between 11 and 16 were the least likely of all age groups to quit successfully."
PA