Around 40 percent of males aged 15 to 24, and 25 percent of females in the same age group are heavy drinkers - defined as consuming more than 21 standard drinks per week for men and more than 14 for women. Alcohol abuse is a major cause of premature death, preventable ill health, social harm and psychological damage to the drinker and those close to them. Alcohol abuse by young people is of particular concern. While experimentation with alcohol and drugs is a normal part of adolescent development, those regularly drinking to excess are less likely to appreciate the need for treatment. Excessive use of alcohol also puts young people at risk of sexually transmitted disease and unwanted pregnancy.
Cannabis is the third most widely used drug after tobacco and alcohol.
Fifteen percent of New Zealanders aged 15 to 45 describe themselves as current users and one percent in this age group are daily users. Heavy, persisting use of cannabis has been shown to cause subtle impairment of intellectual abilities such as attention, concentration and problem solving and this is especially harmful to children and adolescents as it will interfere with maturation and development. It is also damaging to those with mental disorders, especially psychosis. Smoking cannabis can cause respiratory problems in the same way as tobacco. Early intervention with problem drinkers is effective.