Substance abuse and what we get out of it

Ponder this: 42 per cent of people between 19 and 26 interviewed for the British Crime Survey in 1998 admitted to having used cannabis, 14 per cent during the last month, 1 per cent admitted to ever having used heroin, 6 per cent cocaine, 20 per cent amphetamines and 10 per cent ecstasy. It is reckoned that 35 per cent of the population smoke and 90 per cent use alcohol. All in all, at any one time, a lot of people are stoned out of their minds, to use a colloquialism.

This is a good book and Ciaran Regan aims it at the general reader whose biological knowledge he probably overestimates. Many highly intelligent non-scientists will find his explanation of the ionic theory of nerve conduction pure Martian. However, Regan writes well with fluency, energy and style, trying successfully to explain complex neurobiological science in an honest and simple, clear way. With the appropriate educational background, this book provides an excellent foundation for understanding how drugs of addiction affect the brain and lead to addiction, craving and withdrawal.

He does this with a fine eye to the history of the subject and its cultural context. Did you know that nicotine is named after the tobacco plant Nicotiana tabacum , which in turn is named after Jean Nicot de Villemain, an ambassador to the king of France in the mid-16th century? I do not wish even to think about witches absorbing atropine, hyoscine and scopolamine from the "greased shaft" of their broomsticks.

In the process of dealing with the actions of addictive drugs Regan covers a great deal of up-to-date neuroscience, for he himself is an expert in the processes by which the brain changes its own structure and function as it learns from experience, be it sensorial or, as with drugs, chemical. This is a relatively new and important area of neuroscience that has far-reaching implications in many fields. Regan may not be far from the truth when he asserts that drug use has the potential to alter the mind and the evolution of societies: consider the current concern with the use of alcohol by the young and its link to violent crime.

Why is it that the knowledge that heroin affects the brain does not stop people becoming heroin addicts? But then knowing that there is something wrong with your brain does not make you feel less depressed when you are suffering from a depressive illness. I shall have to ask my philosopher friends about the dichotomy between the intellectual and the visceral mind. Current science is not going to solve that problem.

David G. Grahame-Smith is emeritus professor of clinical pharmacology, University of Oxford.