Covariates and predictors included in the analysis
| Variable | Definition |
|---|---|
| Sex—covariate | Male, female |
| Grade—covariate | Four categories: 9th, 10th, 11th, 12th |
| Mental health measures | |
| Psychological distress | Moderate to high vs low psychological distress in the past 4 weeks GHQ25 |
| Used prescribed medication to reduce anxiety, depression or both | Taking prescribed medication in the past 12 months for anxiety, depression or both (yes=1, 0 otherwise) |
| Suicidal ideation | Seriously considered suicide in the past 12 months (yes=1, 0 otherwise) |
| Suicide attempt | Attempted to commit suicide in the past 12 months (yes=1, 0 otherwise) |
| Called a crisis or help line in past 12 months | Called a youth crisis or help line in past 12 months for help (yes=1; 0 otherwise) |
| Used prescribed medication to treat ADHD | Use of prescribed medication in the past 12 months to treat ADHD (yes=1, 0 otherwise) |
| Self-rated mental health status | Reported excellent/good mental health vs fair or poor mental health (yes=1; 0 otherwise) |
| Self-rated health status | Reporting excellent/good health vs fair or poor health in general (yes=1; 0 otherwise) |
| Violent and non-violent conduct behaviours (perpetrator or victim) | |
| Drove a car without the owner's permission | Taken the car for a ride without the owner's permission at least once in the past 12 months (yes=1; 0 otherwise) |
| Damage to property | Damaged something on purpose that did not belong to you at least once in past 12 months (yes=1; 0 otherwise) |
| Sold marijuana or hashish at school | Sold marijuana or hashish at least once in the past 12 months (yes=1; 0 otherwise) |
| Stealing (things worth 50$ or less) | Taken things worth $50 or less at least once in the past 12 months (yes=1; 0 otherwise) |
| Stealing (things worth more than 50$) | Taken things worth $50 or more at least once in the past 12 months (yes=1; 0 otherwise) |
| Physical violence (in purpose) | Beat up, hurt anyone on purpose at least once in the past 12 months (yes=1; 0 otherwise) |
| Physical violence at school | Engaged in a physical fight on school property at least once in the past 12 months (yes=1; 0 otherwise) |
| Breaking into property | Broken into a locked building other than one's own at least once in the past 12 months (yes=1; 0 otherwise) |
| Possession of a weapon (eg, gun and knife) on school property | Carried a weapon such as a gun or a knife at least once in the past 12 months (yes=1; 0 otherwise) |
| Running from home | Ran away from home in the past 12 months (yes=1; 0 otherwise) |
| Set fire | Set something on fire you were not supposed to at least once in the past 12 months (yes=1; 0 otherwise) |
| Bullied others | Bullied others at school at least once in the past 12 months (yes=1; 0 otherwise) |
| Being threatened with a gun or weapon at school (Victim) | Was threatened with a gun or a weapon on school property in the past 12 months (yes=1; 0 otherwise) |
| Being bullied at school (Victim) | Was bullied at school at least once in the past 12 months (yes=1; 0 otherwise) |
| Being bullied through the internet (Victim) | Was bullied through the internet at least once in the past 12 months (yes=1; 0 otherwise) |
ADHD, Attention deficit hyperactivity disorder; GHQ, General Health Questionnaire