It's the parrots I feel sorry for. And the dogs and cats - upwards of 632,000 of them, apparently - who were taking Prozac to alleviate the symptoms of depression and, now that a University of Hull study has shown that SSRIs work no better than a placebo for a majority of patients with mild to severe depression, will presumably have to come off it. Alas, poor Polly. What will she do now? Try a talking cure, perhaps, with one of the 3,600 new therapists whose training has just been announced by the Government.

One way and another it has been hard to avoid depression in the week's news. Apart from depressed animals and ineffective SSRIs, The Times reported that “pressures of consumerism make children depressed”. Elsewhere a study found that more than 1.2 million elderly people are lonely.

So that's pets, old people and children sunk in gloom. Are things any better among the working population? Apparently not: working mothers are in despair because their careers are ruined by employers who won't allow them to work flexibly, while everyone else is worried sick because rates of heart disease, which had been falling for the past 30 years, are picking up again among 35 to 54-year-olds, thanks to our habit of self-medicating for stress with comfort eating, binge drinking and slumping on the sofa in front of The Bill instead of going to the gym.

“We're all doomed,” I tell the cat, who utters a despairing hiss (he's depressed because Bigger Cats keep standing on the garden wall and sneering at him). I'm just reaching for a spot of self-medication in the form of the last of the sloe gin when an e-mail flies into my inbox. It is a press release, headed “Are there benefits to having depression?” Funnily enough, I can think of several. But let us read on, for the press release brings news of How Sadness Survived, a book by Dr Paul Keedwell, a specialist at the Institute of Psychiatry, who proposes, say his publishers, “that depression can lead to increased resilience, empathy and creativity of thought. Examples of brilliant and successful people who have suffered from the condition - from Michelangelo to Winston Churchill - are highlighted.”

I bet they are. But while it's always agreeable to find oneself in distinguished company, when I was struggling with intractable depression 15 years ago, the thought that I was following a path already trodden by a legion of the melancholy famous was no help at all. I become more interested when Dr Keedwell starts talking about his patients' perception of themselves as “broken”. My own depression, having been royally ignored by my GP, was, once it became acute, treated at the Maudsley with humanity and a sense of urgency. I was given an SSRI, which I resisted (because I clung to some writerly notion of “authentic” experience, rather than the drug-muffled alternative). When I did finally take it, I thought it was a swizz: I'd been expecting undignified euphoria but felt just as bleak as usual. Psychotherapy I found simply sinister.

What did the trick was an informal twice-weekly chat to a kind registrar whose unenviable job it was to listen to the agonised ramblings of the mad people of SE5. After about six months I suddenly looked at him and saw that he was exhausted. Up to that point, I had thought of myself as broken like a piece of china: never as strong again. The moment in which I saw that I had reduced this poor young man to a state of drained boredom was also the moment in which I realised that I had been broken like a bone and, like a bone, mended again as good as new.

Better, in fact, because I was now able to make a distinction that I had not made before, between sadness and depression. Young people, particularly, rather fancy sadness. I did myself. I thought it interesting and romantic and was startled by the fury with which Montaigne denounces tristesse in his essay on sadness. “A daft and monstrous adornment,” he calls it. “I neither like it nor think well of it, even though the world, by common consent, has decided to honour it with special favour.”

Having drifted into the Maudsley rather in love with sadness, I came out again sharing Montaigne's view of it as a monstrous waste of time. How to keep it at bay is the question - to which an SSRI has been, until now, a convenient answer. Averse to pills, I had been self-medicating since childhood with books. Trollope and Thackeray kept me going for ages and it is to them, as well as to more modern authors, that I return these days. Chick-lit is useless - intelligent understanding of the human condition is what's needed: Jane Gardam, Helen Simpson, Philip Hensher are all sovereign against melancholy. I thought this was just my quirk and was amazed to find that Jane Davis, of the Reader Centre at the University of Liverpool, has pioneered bibliotherapy as a formal treatment of what Lewis Wolpert called “malignant sadness”.

Bibliophilia provided my other great stratagem: there can't be many people, these days, who have read every word of Robert Burton's eccentric treatise The Anatomy of Melancholy, but I am one of them. And on the final page of my copy I found the indispensable maxim which that great melancholic, Dr Johnson, and many others since (including me) have adopted as their rule of life: “Be not solitary, be not idle”.

Burton doesn't mention pets and exercise, though both of those are encompassed by his helpful aphorism. My own stratagems for keeping sadness away include, in no particular order: work, outdoor exercise (walking, riding) every day, friends, books, retail therapy (in moderation), gardening and the company of animals. I keep thinking that if only we could somehow engineer a meeting between the depressed children, the stressed pets and the lonely old people, we could do away with sadness and its grim outriders, loneliness and academic failure, in a single elegant, drug-free gesture.

Earth didn't move for me

One of the things that would be depressing me at the moment, if only I were succumbing to sadness, would be the decrepit state of my house. So I can't say I regret not having had my tottering chimney-pot precipitated through my worm-eaten rafters by the great earthquake of February '08. Still, sensitive as I am, I can't help feeling a bit miffed that everyone seems to have noticed it but me. A farmer friend who lives miles from the epicentre, in the soggy wilds of the Kent marshes, claims to have felt “uneasy” in the small hours when the quake was occurring. My friend Matron telephones excitedly from Slough to boast that she woke to find a picture of a fish and several enamel plates (also bearing the images of fish, spookily enough) shaken from their accustomed places to the floor. Also, her mother (in Oxfordshire) had felt an intangible sense of perturbation. Alone of all my acquaintance, I seem to have slept through the earthshaking.

Double trouble

Perhaps my problem is an excessive attachment to my own bed. I got it from Heals decades ago (“Oh darling,” said my mother, “What do you need a double bed for?”) and occasionally make my son's flesh creep by reminding him that he was conceived in it. It is a very good bed: so large as to fill my tiny bedroom with inches to spare. To my chagrin, the cat and the son have taken to treating it as a kind of common room. When I want to get into it, I frequently have to clear them and their impedimenta - books, computers, the occasional mouse - off it. In short, I am highly sympathetic to President Sarkozy's sudden curtailment of his state visit to Britain from two nights to one. “He prefers to sleep in his own bed,” said an aide. Given their habit of flying their own sheets and pillows around the world, I'm sure the Royal Family will understand.

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