Teenagers as young as 14 are using cannabis every day, according to a study by Queen's University Belfast.
Researchers found many cannabis users had other social problems
The researchers found about one in 10 cannabis-smoking teenagers they surveyed were using the drug daily.
Dr Patrick McCrystal said cannabis use at a young age could lead to mental illness and other problems.
"These young people are telling us that by the age of 15 they have moved beyond experimental or recreational use of an illegal drug to more sustained usage."
He said teenage daily cannabis users were "more likely to spend their evenings away from the family home, have poor levels of communication with their families, and be disaffected with school".
The researchers found that 70% of frequent users were boys, while almost two-thirds of all the cannabis smokers belonged to the lowest socio-economic groups.
The study further indicated high levels of delinquency and anti-social behaviour by daily users which may have become part of their 'lifestyle activities'.
Of daily cannabis smokers, a quarter reported being in trouble with the police on more than 10 occasions while almost one fifth had been summoned to court in the year prior to the survey.
Dr McCrystal said the lifestyles of high-level users "may provide valuable insights for education and prevention strategies for the future".
He said they hoped to "more fully understand how drug use is shaped by lifestyle, and conversely, how drug use reshapes lifestyle".
The Youth Development Study by the Queen's Institute of Child Care Research is a long-term study of adolescent drug use.
Some 4,000 teenagers from 43 schools in Belfast, Ballymena and Downpatrick have taken part each year since they entered secondary education.