KEY POINTS:
A new study has found that a third of frequent cannabis users at New Zealand high schools have been sexually abused.
The author, Annabel Prescott, told an addictions conference in Auckland yesterday that sexual abuse was the only key "risk factor" that showed up in a statistical analysis of all factors associated with heavy cannabis use in the Youth 2000 survey of 9570 students at 114 New Zealand high schools.
The analysis found that heavy cannabis users were also more likely to be violent, get involved in fights, ride in cars being driven dangerously, have unprotected sex, be clinically depressed and attempt suicide.
It found four "protective" factors that cut the chances of the students using cannabis heavily: getting "enough time" with their parents; feeling part of their school; feeling that school attendance was important; and attending a church, shrine or mosque.
Mrs Prescott said the study showed that heavy cannabis use was a marker of wider problems that should all be dealt with "holistically".
"A young person should be able to go to one place without having to go to multiple services and having to retell their story to lots of health services."
The study found that 35 per cent of both boys and girls at high schools, mostly aged 13 to 17, had used cannabis. Of those, about half had only tried it, and another third used it only about once a month.
Mrs Prescott found that the links with violence, depression and other health problems only kicked in for the remaining fifth of male cannabis users, and fewer than a sixth of female users, who used the drug at least once a week.
Asked whether they had experienced unwanted sexual touching or been made to do anything sexual that they didn't want to do, a third of the high cannabis users said "yes", compared with less than a fifth of other students.
Higher proportions of cannabis users had also been physically abused and bullied, but the differences were less significant after controlling for other factors.
The study found that only about 44 per cent of the high cannabis users felt they got enough time with their parents, compared with 62 per cent of other students.
Only about 64 per cent felt they were part of their school, compared with about 84 per cent of other students. And only about 8 per cent attended a church or other place of worship, compared with about 18 per cent of other students.
In contrast, the survey found no significant difference between high cannabis users and others when asked simply how important their beliefs were to them.
Mrs Prescott concluded that churches might be connecting young people with adult mentors, providing activities such as music tuition that students from poorer homes could not afford elsewhere, and teaching them leadership and speaking skills.
The study did not ask about involvement in sports clubs or other cultural organisations.
