Adolescents often engage in problem behaviours including smoking, drinking alcohol, gambling, and antisocial behaviour. The authors of this study aimed to identify subgroups of adolescents based on their engagement in smoking, drinking, gambling, and antisocial behaviours. They used data from a large survey of 15- to 18-year-olds in Västmanland, Sweden. The authors identified four subgroups of adolescents. Two groups reported high levels of problem gambling along with high levels of alcohol use and antisocial behaviour. One group also had high rate of daily smoking. The third group reported high endorsement of antisocial behaviour but low levels of other problem behaviours. The fourth group reported low levels of all problem behaviours. The two groups that gambled also had the greatest level of mental health problems, including ADHD symptoms and depression.