WHY ARE we so miserable? Because we have, by unfortunate chance, developed a world for ourselves that clashes with our evolutionary needs. Money, computers, public transport, pollution, deadlines and over-in-a- blink orgasms: none of this is very satisfying for a body that is still expecting to hunt, gather and spend the rest of the day sitting round the fire having sex. Even if we can accept Geri Halliwell as our cultural leader in the abstract, it doesn't make sense to evolution and we are left with a feeling of dissatisfaction.

Which is why one doctor has written that anti-depressants should be available on demand, like the pill. We live in an artificial society and the only way to deal with it is artificially.

Dr Bruce Charlton from the Department of Psychology at the University of Newcastle, writing in the new issue of the Royal Society of Medicine Journal, says: "We are living in unnatural conditions. Society is unlikely to change in the foreseeable future, so it is a question of what can we do to change to adapt to society. There is a spectrum of actions that anti-depressants perform - helping anxiety, tension, fearfulness; some help with sleep or with lost appetite. They don't always work. There are, rarely, serious side-effects but generally they are very low risk. They are not happy pills; they are more like a sort of painkiller, an analgesic."

We are the human equivalent of the giant panda in captivity - so miserable it can't even mate. And scientists no longer think that depression is a "them and us" disease - that there are depressives and there are normal people. In the west, depression is a continuum from the completely suicidal to the mildly hacked off. We all suffer.

The continuum idea is backed up by recent evidence from trials that suggests that so-called healthy people can benefit from taking anti-depressants like Seroxat, known as the "shyness drug", and Prozac. Those taking these drugs say they feel more comfortable in social situations, and have lower levels of unpleasant emotions.

Most of us could benefit from anti-depressants, say, to cope with the minor illness that is a constant downer in life. "It isn't implausible that most of us are ill," says Dr Charlton. "Cities have created upper- respiratory tract infections two or three times a year." Cities give us allergies, infections, paranoia, exhaustion - and that's just me.

Yet getting anti-depressants is still a means test. No good going to the doctor feeling a bit low; you have to wait until you've deteriorated. "You have to prove you deserve the drug," says Dr Charlton. "You have to have severe persistent low feelings, crying easily, poor sleep, loss of appetite, libido and suicidal thoughts."

And the fact you have to be exceptionally miserable to get the drugs of course makes them more taboo. "I used to think that anti-depressants were a big step. Now I see them like taking medicine for any physical disease," says Helen, 29, a copywriter. "I went through periodic phases of feeling miserable and binge eating - probably a more extreme version of what many people feel like. I was resistant to taking drugs because I thought there were things in my life that were making me miserable that I ought to be able to sort out on my own. But my father said, 'Take them and you will be more capable of dealing with your problems.'

"When I started taking the Prozac I soon achieved an unusual state of balance. I was more able to derive pleasure from the moment. I could enjoy minor achievements at work. I only took Prozac for four or five months at a time, but I remain more stable, knowing I can go back at any time."

"I see anti-depressants as a lifestyle drug," says Dr Charlton. "Like the contraceptive pill which has been available for 30 years on the principle that, as long as there is no significant danger from side effects, doctors should prescribe it to anyone who asks for it."

Since this column is meant to be advisory I will end on that note: if you want anti-depressants, sell your symptoms like you'd write a CV. Talk it up.