GRAPHIC television advertisements that show crystal methamphetamine users being raped, threatening to kill their parents and prostituting themselves make teenagers four times more likely to approve of using the drug regularly rather than scaring them into avoiding it, an Australian study has found.

The ads, shown in the United States, are similar to a Federal Government-funded television campaign aired in Australia last year, which showed young people being arrested, picking at scabs and facing unemployment, but researchers say their studies have proven they are too graphic to be taken seriously and are a waste of money.

The Montana Meth Project, a national drug prevention program based in the north-western US state, saturated the national market with 45,000 ads on television, 35,000 on radio, 10,000 in print and 1000 on billboards between 2005 and this year, and claimed its shock tactics reduced ice use in the state by 45 per cent in teenagers and 72 per cent in adults.

But researchers at the University of Western Australia studied feedback from thousands of teenagers exposed to the campaign and found a threefold increase in the percentage of teenagers who said they did not believe using ice was risky and a fourfold increase in those who strongly approved of regular ice use. Half thought the campaign exaggerated the risks.