This week Colorado became the first US state to legalise cannabis for recreational use.
Colorado voted in November 2012 for a change in the law which came into effect on New Year’s Day – now adults over the age of 21 can purchase cannabis for personal use on private premises.
But Kevin Sabet, of Smart Approaches to Marijuana (SAM), warned that legalisation could have negative consequences.
“This is an industry that makes money off addiction,” he said.
“There will still be a black market to serve people who are ineligible to buy on a legal market, especially kids,” he added.
“It is almost the worst of both worlds.”
“We’re opening the doors to allowing a new, powerful industry to downplay the effects of a substance they will be profiting off of and to downplay the effects of addiction”, he said.
He added that children could be targeted and deceived into thinking the drug is harmless.
He also said legalisation is not “inevitable” in other states and his organisation will fight against changes in the law.
Patrick Kennedy, a former Congressman and recovering drug addict, said: “We don’t have to have other states go down this road and have to learn the same hard lessons that residents of Colorado are already learning.”
An estimated 37 shops with recreational licences opened for business on Wednesday – 136 retail stores in total have been licensed to sell cannabis across the state.
Users can possess up to one ounce at a time under the law, which is the most liberal cannabis policy in the world.
An editorial in The Independent yesterday said the UK should follow in Colorado’s footsteps.
It said, “we hope that the enlightened and experimental policies pursued in Colorado and Washington, as well as in Uruguay in Latin America, will start to shake our own political establishment out of its complacent reliance on a policy based on prohibitions pure and simple”.
Uruguay recently came under fire after it legalised growing, selling and consuming cannabis. A UN drugs group, the International Narcotics Control Board, warned that the move could be unlawful.