More Americans are 'just saying yes'

Nancy Reagan once told them to "just say no", but 13% of Americans no longer heed the former first lady's call as they admit to smoking dope on a regular basis.

In a far cry from the 1980s when the Reagan administration stepped up the war on drugs, more and more Americans are changing their ideas to view marijuana use as less harmful.

A study released in yesterday's Lancet magazine found an estimated 13% of all adults in the US, or 31.9 million people, regularly use the drug. The figure was 10% in 2002.

The data comes from the annual US National Survey on Drug Use and Health that questioned almost 600,000 adults between 2002 and 2014.

It found people were smoking more often and more potent forms of weed.

Respondents were asked: "How much do people risk harming themselves physically and in other ways when they smoke marijuana once or twice a week?"

In 2002, half of all respondents thought that people were harming themselves, but the latest data suggests only a third view weed as problematic.

The authors suggest that the legalisation of medical marijuana may have contributed to the perception of the drug as safe.

Even as use increases, scientists said addiction and psychiatric problems such as schizophrenia linked to dagga smoking remained constant, affecting 1.5% of all US adults and 15% of users.

About 3.5% of respondents used weed daily.

Extrapolating this data to the US population, the number of daily users rose from 3 million in 2002 to 8.4 million.

Decreased perception of risk can be a good predictor of drug use, said scientists.

"Although shifts in perceived risk have historically been important predictors of adolescent marijuana trends, no previous research has examined this relationship in adults," said Wilson Compton of the National Institute on Drug Abuse, National Institutes of Health.

"State laws related to marijuana use in the US have changed considerably over the past 20 years, with medical marijuana now legalised in 25 states and the District of Columbia."

The legalisation of dagga use in South Africa is still under discussion.