Shapiro stresses that vulnerable groups or those, especially young men, with a pre-existing tendency to mental health problems, are more likely to get into difficulty with cannabis.
"But for a lot of young boys it is about wasting time. And wasting time is the biggest threat they'll face. Smoke it regularly for a couple of years and you're doing nothing else. So while obviously the mental health issues we know about are at the more dramatic end of things, there are other issues and we have to be careful and look out for the people likely to get into the most serious problems, who are those self-medicating against problems in the family, at school, with their friends." He feels there are myths around skunk and that strong cannabis is nothing new. "Even in the 1960s we had Nepalese temple balls and Thai sticks, the connoisseurs' cannabis if you like."
General statistics on drug use show the heroin-using population is ageing: it is not attracting new users. But cheap alcohol and cannabis are more attractive as patterns of drug use shift. "At the moment, skunk is supplied by gangs growing it in houses and flats, and the police are getting good at shutting those down. There is evidence there is a growing demand for imported cannabis again, so if that goes on you might just see another shift away from it."
Many people believe that waiting for change is not enough and legislation is needed to deal with the problem. Helen Sello is in her mid-50s and her son is schizophrenic. "I'm not sure which one thing caused the other," she said. "Did the schizophrenia come from the drug or was he self-medicating? It's not really a useful thing to do if you have any high risk toward mental illness, and who knows who can pick and choose?
"I thought it was perfectly harmless. I thought I'd prefer him to do that more than getting drunk. I support legalisation, not because I think young people take a great deal of notice of the law – they don't – but because I think that with legalisation comes control. Give people more information: vulnerable young people need to know what this drug can do. If anything makes me really angry it is that this is such a polarised debate, an immature debate. It's either that cannabis is good or it's bad."
