Most people see addiction as a transition between behaviour which is voluntary and under their own control to a form of behaviour determined by the pharmacology of the brain, where the addict can no longer make decisions.
John Davies, professor of psychology at Strathclyde University, believes this is a damaging myth which undermines the chances of addicts getting control of their habit. "The pharmacology of drug use is not the pharmacology of making decisions," he argues.
"If the heart of the definition is that addicts' behaviour is not theirs to control, whereas the rest of us have free will, that's ridiculous."
Professor Davies, whose research in the area has culminated in a book, The Myth of Addiction, says that addiction is the result of decisions which may be ill-advised, but are nonetheless subjectively rational for the person taking them.
He points out that there is currently no social class barrier among young people taking drugs. A student poll at one Scottish university revealed that 68 per cent had taken illicit drugs. But damaging drug use is much more prevalent in deprived inner city areas. The distinction in these areas is that people are facing problems of crime, unemployment and the lack of any clear ability to plan for the future, Professor Davies says.
"Someone like me can plan holidays, things they want to buy, can see what their goals are and have a reasonable expectation that they will achieve them. If someone like me goes out for a binge on Friday and Saturday and gets wrecked, there's a very good reason for getting themselves sorted out, ready for Monday morning. But if Sunday is no different from Monday or Tuesday, why should they be motivated to do anything, especially if taking drugs is as good as life gets?" He says there is a growing body of evidence that people who believe they are helplessly addicted are far less likely to attempt to control their habit, and far less likely to succeed when they do.
Treatment strategies vary, with some agencies encouraging a sense of personal responsibility, while others explicitly rule this out as a precondition of treatment, Professor Davies says.
"This view of helplessness is the single most disabling feature of addiction. It doesn't give them permission to take charge. They think addiction is the same as a broken leg; you take it to the doctor who fixes it or doesn't fix it, and it's nothing to do with you."