Drinking contributes to the three leading causes of death among teenagers: unintentional injuries, homicide and suicide. In an American study, one in 10 teens reported being influenced by alcohol during a fight. This same group were also more likely to injure themselves or others during the fight. The prevalence of risk-taking behaviours increases in adolescence and the likelihood of injury increases further when alcohol is also involved.

In Western Australia, almost one in four (23%) young people who drank in the last week reported having an argument and 13% reported hitting someone or having a fight.

Early onset of alcohol use as a teenager is related to more risky patterns of use in the long-term. Delaying the onset of alcohol use is linked to more moderate and less risky patterns of use in adulthood, particularly as drinking alcohol as a teen is also associated with harmful adult outcomes.

For example, alcohol use in adolescence can see teens who drink being at higher risk of later alcohol use disorders than their non-drinking adolescent peers. The Victorian Adolescent Health Cohort Study (VAHCS) have identified frequent teen drinking and antisocial behaviour as key predictors of alcohol use disorders at 21 years of age. Teen drinking patterns often continue into young adulthood and later adult life, including progression to alcohol dependence in adulthood.

Alcohol use, especially when initiated at a young age, elevates the risk of many mental health issues and social problems. The nature of the relationship between alcohol use and mental health issues in adolescence is somewhat reciprocal. Young people with certain mental health disorders are more likely to initiate alcohol use and accelerate their use throughout adolescence. In turn, alcohol use may contribute to poor mental health. One of the major complications of teenage alcohol use is self-harm, having suicidal thoughts and suicide, especially in teens with major depression.

Risky behaviours that lead to chronic non-communicable diseases in later life, including tobacco, alcohol, and illicit substance use, unsafe sex, obesity, and lack of physical activity, typically emerge around adolescence. Almost one in 10 young people reported having sex while drinking and later regretting it, and one in 10 reported either having not used contraception or not used a condom or both.

The National Health and Medical Research Council guidelines to reduce health risks from drinking emphasise the importance of delaying the initiation of drinking for as long as possible as a key factor in limiting alcohol-related health issues during a person's lifetime. The evidence suggests that earlier initiation of drinking is related to more frequent and higher quantity alcohol consumption in adolescence, and these patterns are in turn related to the development of alcohol-related harms in adolescence and adulthood. There is some evidence to suggest that the later teenagers delay their first alcoholic drink, the less likely they are to become regular consumers of alcohol, and delaying the onset of drinking reduces consumption levels in adulthood.