It may have been the happiest day of the year on 19 June, but we are already into the hangover. Figures obtained by the Liberal Democrats reveal that antidepressant prescription numbers are going through the roof – 36m scripts were handed out to patients in England last year, a rise of 2.1m on 2007. That's almost one for every adult. Lib Dem health spokesman Norman Lamb is right to describe the figures as "deeply disturbing".

Lamb has demanded improved help for people whose problems are recession-related. It's true that financial woes create more distress, but we shouldn't use the economy as a smokescreen for what is a longer-term malaise. Antidepressant use has been going up for years – prescriptions have more than tripled since the early 1990s. We have not become a Prozac nation overnight.

So what is going on? Are we genuinely becoming more miserable? That's part of the story – according to official statistics, the percentage of people with a "common mental disorder (pdf)" increased from 15.5% in 1993 to 17.6% in 2007 (that's a million extra unhappy people across the UK). Some of these inevitably wind up at the GP surgery, seeking relief.

But perhaps more instructive is what happens next. Most GPs respond to mental health problems by reaching for the prescription pad, even though guidelines from the National Institute For Clinical Excellence generally recommend psychological therapies. To some extent, doctors do this because they have little choice – more than three-quarters have prescribed medication despite thinking an alternative would be more appropriate. Most do so because there are no other options available – decent psychotherapy services are still few and far between, and often have long waiting lists.

However, medics also prescribe drugs because that's what they are trained to do – pills have long been their (and our) default response to depression. The dominant view of psychiatric illness is that chemical imbalances in the brain are mostly to blame, and that they can be controlled with pharmaceuticals. This line has been peddled hard by drug companies, and for a long time it was accepted almost without question — the reception which greeted the arrival of Prozac and the other SSRI antidepressants (which were supposed to counter the "imbalances") was nothing short of hysterical. Reality has been more prosaic: a recent review found the SSRIs barely more effective than a placebo pill. Still, the NHS bill (pdf) for prescribing them runs into hundreds of millions of pounds a year.

It's a crazy situation, and the tide may be turning. The dubious tricks used by drug companies to make their products seem more effective are becoming widely known (thanks in part to vocal critics from inside medicine, such as this paper's Ben Goldacre), while the government is beginning to invest in proven non-drug alternatives, such as psychotherapy. Research into the biological bases of mental ill-health is floundering – a study just released casts serious doubt on the existence of a previously heralded "depression risk gene". Meanwhile, there is a growing evidence base for simple, socially based steps everyone can take to improve their wellbeing. These include building good relationships, lifelong learning, being kind to others and exercise – not rocket science, but somehow we seem to have forgotten them.

And this week, renowned clinical psychologist Richard Bentall publishes Doctoring The Mind: Why Psychiatric Treatments Fail. In meticulously referenced detail, Bentall documents the shocking failures of biological psychiatry and the drug-based mental health system it perpetuates, and calls for an evidence-based alternative that offers patients support, care and respect. The book effects a courageous, comprehensive demolition of the status quo, and offers a radical vision of a more humane future for services – it should be required reading for everyone with a hand in mental health policy.

It won't be easy to make such radical changes in the way we approach wellbeing. It means giving up hope of medical "quick fixes", at least until they are as good as their makers claim, and turning instead towards methods that are far less financially profitable, and which require hard work on the part of professionals, patients, government and the rest of us. As well as an overhaul of services, it means tackling social fragmentation, greed-based economics and the stress created by a speedy, sensationalist culture. And it means starting a mature debate based on understanding rather than fear of the mind, promoting the ways we can look after our psychological as well as our physical health. That may sound like a tall order, but until we make a start, the queue of glum-looking folk at the chemist will just keep on getting longer.