Many of the people who oppose the legalisation of cannabis want to protect young people from what they see as its damaging effects. "It's all very well for trendy oldies but children have a right to a clean environment," says Jim Comberton, chief executive of Coolmine House, a drug-free prevention and recovery programme in Dublin.
"Using cannabis turns young people off, so they lose energy and are not interested in what's going on at school," he adds. "Teachers start assuming the kid is stupid, not realising he's smoking cannabis."
"There is a loss of concentration and short-term memory, and a slowing of the learning process," adds Dr Michael ffrench O'Carroll, author of a recently published book entitled The Irish Drugs Epidemic. "I see youngsters who take massive amounts of cannabis every day. They are all dropouts from education and training programmes." Dr ffrench O'Carroll is the founder of Arbour House in Cork, the Southern Health Board's addiction treatment centre, and is currently addiction consultant at Sister Consilio's Cuan Mhuire Centres. He believes cannabis use can even trigger latent schizophrenia.
Both he and Jim Comberton are concerned about cannabis as it is taken in combination with alcohol: "If you get into a cannabis-smoking crowd, you're almost certain to be using it with booze, and the two, taken together, are much more potent," says Comberton.
Grainne Kenny, International Chair of EURAD (Europe Against Drugs), says that the relaxed attitude to cannabis use in the Netherlands has led to "a huge rate of absenteeism from work". She has recently been in Strasbourg to lobby Irish MEPS to vote "no" to a recent proposal by the EU Civil Liberties Committee to legalise cannabis and to make hard drugs available on prescription.
She is not convinced by the arguments put forward by those who say cannabis can help certain medical problems: "It's like people smoke a cigarette because they think it will calm their nerves. They get stoned so they think they're getting better."
She believes that cannabis is a gateway drug: "I'm a counsellor with young people, many of whom are addicted to heroin and who started out smoking cannabis. And these are from every social class." She concludes: "Alcohol and cigarettes are our most abused drugs because they are socially acceptable and legally available."
She does not think the Irish legal system is unfairly harsh on young people who are caught with small amounts of cannabis for personal use: "We have good laws here; nobody wants to give a person a criminal record."
This is confirmed by Det Chief Supt Kevin Carthy, head of the Garda National Drugs Unit: "I've never known of anyone going to jail for possessing a small amount of cannabis for personal use. Each case is taken on its own merits. You might get probation, or a fine. Young people can come in to our juvenile referral scheme where they are given a caution if they agree to take our advice and don't re-offend. We feel a conviction for drugs is a very serious thing and we don't want to affect their employment prospects."
Nevertheless, "Irish law does not distinguish between cannabis and other drugs. We don't use terms like soft drugs and hard drugs. The fact is that all drugs are harmful. Cannabis is a mind-altering substance, and the research is there to show that it is a gateway drug. The National Household Survey in the US found that between 1991 and 1993, people who used cannabis were 104 times more likely to use cocaine than people who had never used cannabis".
He argues: "if you decriminalise cannabis, more people will use it and become dependent on it." He cites the case of Alaska, where in 1971, a law was passed allowing people to possess 4 oz of cannabis for personal use: "There was a follow-up survey which found that, as a result, the number of young people who were using cannabis was twice the national average. The law was changed again in 1992."
As for the argument to decriminalise cannabis for medical purposes, he quotes doctors and medical bodies in the US which do not accept the effectiveness of cannabis in treating disorders such as MS, adding: "We know about the health risks associated with smoking tobacco. It is being outlawed everywhere. It defies logic to argue for the legalisation of smoking cannabis, which is five times more carcinogenic."