Several months ago a television researcher rang to sound out my views on whether antidepressant drugs such as Prozac were "addictive". This had apparently recently been claimed by Charles Medawar, an academic and a well-known critic of the pharmaceutical industry.

Like all family doctors I see a lot of patients with various forms of depression. They come to the surgery weeping and miserable and we discuss what is going on. Many describe the sort of life that would make me frankly suicidal: trapped in a world of dismal housing, little money, aggressive husbands and wayward children, there seems no escape. But when I suggest they might be helped by taking something to cheer them up for a while, they often reply: 'I don't want any antidepressant pills, thank you. Everyone knows they're addictive.' Or words to that effect. Thus they spurn a treatment that could improve their mood and help them break out of the vicious circle of depression. I said this to the researcher, adding that as Medawar was obviously propagating such harmful ideas, he could, as far as I was concerned, take a running jump.

By chance, I recently came across a copy of Medawar's report and I now realise I owe him an apology. The central question he raises is: why is it that since the introduction of Prozac in 1989, the number of prescriptions issued for antidepressants in England has risen from 8.9 million to 13.2 million a year, tripling the costs to the Health Service from £54 million to £147 million?

It would seem unlikely that compared to ten years ago there has been a vast increase in the numbers sufficiently depressed to require drug therapy. It is just possible that depression has been 'under-treated' in the past, with both doctors and patients being discouraged by the side effects common to the earlier types of antidepressants - a dry mouth, blurring of vision and difficulty with concentration. Prozac, by contrast, is a much 'cleaner' drug with fewer side effects. This makes it more acceptable all round; doctors are happier about prescribing it: hence the extraordinary rise in the number of prescriptions.

There is, as Medawar points out, an eerie parallel here with the escalation in the use of tranquillisers such as Valium back in the Sixties and Seventies. For decades, doctors had been prescribing barbiturates for those with anxiety and insomnia, which worked well enough but unfortunately tended to depress the respiration, so those taking an overdose, either accidentally or intentionally, stopped breathing and died. Valium turned out to be almost miraculously safe. Indeed, in the standard tests for toxicity it was claimed the only way someone could be killed by Valium was by being crushed under a ton of tablets.

This concept of Valium as a safe "minor" tranquilliser obviously implied it could be safely prescribed for virtually anyone, including the merely unhappy and those stressed by having a physical illness such as asthma or a peptic ulcer. Virtually anyone turning up to the doctor's surgery could benefit, or at the very least would be done no harm.

The bubble burst in the early Eighties with a demonstration that Valium could induce in some people a state of dependency (which had until then been vigorously denied). In the following few years the number of prescriptions fell by almost 90 per cent.

Similarly, argues Medawar, the runaway success of Prozac might in part be due to doctors' perception that it is a safe, clean drug that they can 'safely' prescribe for anyone. The Royal College of Psychiatrists has given a helping hand by claiming that doctors routinely fail to recognise those who are depressed and thus implying that there are lots more people 'out there' who would benefit from Prozac.

And is it addictive? Here one is up against the same problem as with Valium: whether the return of symptoms following the cessation of treatment represent a recrudescence of the original problem for which the drug was prescribed or is a genuine withdrawal reaction. There are certainly many case reports indicating that Prozac can induce dependency, and Medawar quotes from a new and interesting source - the views of Prozac takers themselves, communicating with each other on the Internet. They describe having to increase the dose steadily to maintain the effect (suggesting tolerance to the drug, another sign of dependency); or say that it can quite suddenly stop working altogether; or that they have difficulty coming off it.

Reading Medawar's paper, I realise that I have been too readily seduced by Prozac's charms. It certainly can transform people's lives, especially those whose depression comes 'out of the blue': but, as the historical parallel with Valium suggests, it is necessary to be vigilant.

 ________