"For many years New Zealand has shared top ranking for youth suicide rates with Finland and Ireland. All three countries have a similar population size, so probably all report and count suicides equally well, but the most striking relevant similarity is the high use of alcohol among youth, which includes, in New Zealand, a prevalent culture of binge drinking.
"Addressing alcohol use and binge drinking in young people in New Zealand is one of the most obvious avenues to reducing both suicide and traffic mortality."
Alcohol was the second-most-important risk factor for suicide after depression, Dr Beautrais said yesterday.
In young people this was probably through the relaxing of inhibitions that occurred with intoxication and could lead to impulsive, aggressive, angry behaviour. This could increase the risk of a suicide attempt, or of doing something the person was later ashamed of, which could increase the risk of suicidal behaviour.
The Government's proposal to partially increase the alcohol purchase age from 18 is expected back before Parliament within weeks in the final reading of the wide-ranging Alcohol Reform Bill.
The bill proposes a split purchase age: 18 in bars and other places with an on-licence, and 20 for off-licence bottle stores, including supermarkets.
Dr Beautrais said that, on its own, the split age was unlikely to have much impact on the suicide rate.