Otago study shows adverse effects are occurring up to the age of 30.
Young adult drinkers dependent on the bottle are nearly 10 times more likely to have had 10 or more sexual partners within several years than people who don't misuse alcohol, a new study shows.
And they are nine times more likely to have committed violent offences.
The study's authors, including Dr Joseph Boden, estimate in the journal Drug and Alcohol Dependence that the elimination of all alcohol misuse could reduce the young adult crime rate by up to 47 per cent.
The research, from Otago University at Christchurch, is based on interviews with around 1000 members of a long-term study who were born in the city in 1977.
The alcohol study draws on answers from when they were aged 21, 25 and 30.
Five per cent met the clinical criteria for alcohol addiction. Up to a quarter had problems with alcohol that were less serious but still affected their daily life to some extent.
Dr Boden said much alcohol research focused on the impact on teenagers - "because they do the most drinking, it peaks at age 21 and drops after that. Our study shows these adverse effects are occurring up to the age of 30".
He said earlier research by his group had indicated the risks of hazardous drinking patterns were now stretching further into adult life because of New Zealand's trend of delaying parenthood, which now on average started in the early 30s.
"It shows people are living this extended adolescence.
"They are partying a lot, carrying on doing these things that they were doing when they were younger. Parenthood knocks this stuff right out of people - the drinking, the drugging. They largely clean themselves up."
Dr Boden said he was disappointed by the weakness of the alcohol law changes passed by Parliament last December.
Alcohol Healthwatch director Rebecca Williams said councils, which were developing local policies under the new law on the location of outlets and trading hours, must take notice of the new findings.
Addiction 'led to guilt and depression'
Kimberley Benson can attest to some of the harms of heavy drinking identified in the Otago University study.
Miss Benson, a 40-year-old administration assistant, began drinking in her late teens, but it was not until about six years ago that alcohol became a problem for her. She found that once she had a drink, "I would not be able to stop".
She now tells of the toll the addiction took on her life - the prosecution for drink-driving, the embarrassing behaviour and memory black-outs, the loneliness of depression and the damage to friendships.
"People don't want to be around someone who has had too much to drink," Miss Benson said.
"I was not a very nice person to be around. I was angry, resentful - not the sort of person I am generally."
Miss Benson sought help at the Capri private hospital in Auckland, where she is now an outpatient, a recovering alcoholic.
Her depression had lifted "just since I have been in recovery - I'm almost eight months sober".
"I didn't realise drinking and depression can go hand-in-hand. I think the drinking caused the depression, definitely.
"It's an awful way to live. You're always feeling guilty, always feeling shame."
YOUNG ADULT DRINKERS
• 10 times more likely to have had 10 or more sexual partners within several years.
• 9 times more likely to have committed violent offences.