Depression is routinely described as an "epidemic". The World Health Organisation predicts that the illness will soon be the second-biggest public health risk after heart disease. Young people, as this newspaper reported recently, are more likely to die from depression than from Aids, cancer and heart disease combined. One person in 20 in Britain is now clinically depressed - about three million in total - and one in five of us will suffer from depression at some point in our lives.
Yet I suspect that the true picture is even worse. The statistics all scream about one form of depression, but I believe that there is another form, much less recognised, that affects millions more people, especially men. I first wondered about this in relation to my own breakdown. It happened over the course of just a few days, in the spring of 1996. I went from a high-octane, glamorous life as a New Labour high flyer to being scarcely able to muster the self-confidence to go to the corner shop for milk. It felt at the time as though I was fine one day, and the next completely crippled. But could such a catastrophic depression really have sprung from nowhere?
At first I thought I had a virus, but after a week or so I realised that physically I felt fine. I wasn't too tired or ill to get up and about, I just had no inclination to do so. I felt bereft, alone (though I wasn't) and hopeless. I had to recognise the surprising but inescapable fact that I was depressed. I started to tell people, which wasn't easy, but it did come as a sort of relief. To be fair to the world of Westminster, people were sympathetic, supportive and ready to give me time to recover.
Little did they, or I, know that recovery would take years. For the first two years I eschewed therapy and stuck to medication (first Prozac, then Effexor). This warded off the worst of it and I was able to work in fits and starts. Many the day, though, I would return from lunch with a journalist or some radio or TV gig and collapse in bed with the covers pulled over my head.
Eventually, I gave in to my friend's urging and went to see a therapist. I started the painful process of examining what had gone so wrong for me, rather than just trying to patch up the wound and soldier on. It was not easy but after two years of once-a-week sessions, I felt I had regained some equilibrium. I had also found something I wanted to do with my life. I wanted to try and help others in the way that I had been helped.
In 2001, I left London for Berkeley, California, where I spent three years training to be a psychotherapist. As I began working with patients in a local community clinic, I noticed a pattern emerging. People would come to therapy with a variety of problems, but, after a few months, it transpired again and again that below the surface was a hidden reservoir of profound melancholia. A depression that they had been hitherto unaware of, except perhaps in the most dim and fleeting way.
I was also struck by the statistic that 70% of people who commit suicide are depressed - that is to say, were showing the classic symptoms prior to taking their own life. But what about the other 30%? Some were doubtless hiding their depression from those close to them, but as anyone who has suffered the illness will tell you, that's quite a trick to pull off over any length of time. I suspect that their depression was actually masked from themselves.
This becomes explicable if we consider the possibility that not one but two types of depression exist. The classic variety, with its familiar list of symptoms and behaviours - joylessness, sleep problems, feelings of hopelessness and so on - I would call blatant depression. One of my friends said she could always tell if I was depressed, before I had even uttered a word. "It's in your eyes," she would say. "They're dead." The other type - and the one I believe may be the true hidden epidemic - I would call latent depression. It remains hidden not only from the outside world, but from oneself.
I've come across five main ways in which this phenomenon is masked, but in order to understand what may be happening, we need to first understand the true meaning of depression. There is a tendency to consider it just a set of behaviours; symptoms to be ticked off on a medical checklist, but at its cold heart, depression is not a preponderance of certain behaviours or feelings. It is an absence of something - contentment, ease, a sense of aliveness. It is, in fact, a sort of death.
In blatant depression, this is easily seen, and is part of any sufferer's self-description. But in latent depression, that absence is not expressed or even acknowledged. Instead, it is covered up. Many people with latent depression appear to be functioning very productively, and if anyone asked them if they felt dead, they would think the question absurd. What matters, however, isn't "feeling" dead, but "being" dead.
Before I became blatantly depressed, I was neither happy or unhappy. My life was a heady mixture of sensation and disassociation, chasing one buzz after another, cut off from any real feelings. In 1998, a scandal known as Lobbygate provoked my deepest slide yet - the one that finally pushed me into therapy. I was taped by an undercover journalist boasting: "There are 17 people who count in this government, and to say I am intimate with all of them is the understatement of the century." The irony is, I wasn't capable of being intimate with anyone.
My depression didn't come out of the blue. It just came out into the open. I had masked it with grandiose, high-powered but self-centred living. Others mask theirs by spending huge amounts of time and energy constructing other ways to suffer, so that the real demon need never be faced. Anxiety, addictions, compulsions (perhaps an obsession with work or shopping), aggression and an emotional detachment from others may all be disguising depression from oneself and the outside world.
Similarly, psychosomatic illnesses, aches and pains, especially backaches, eating disorders and self-harm by cutting all provide ways of converting latent depression into something more visible and, though it is hard to believe, more bearable.
One clue that all these conditions and behaviours may have an underlying connection to depression is that they can often be treated with the very same drugs that alleviate blatant depression. Prozac or other drugs in the SSRI family are prescribed for anxiety, eating disorders, alcoholism and obsessive-compulsive disorder, indicating, at the very least, that there are overlaps in the underlying brain chemistry of these conditions.
These phenomena may not always mask depression, of course. But my own experience, as both a patient and a therapist, makes me believe that latent depression is more common than we think. It may be more widespread, in fact, than its more blatant brother.
However, if the body and mind have devised ingenious methods of keeping you and your depression unacquainted, where is the benefit in digging through a layer of vaguely problematic behaviour - a weakness with credit cards and drink, say - if the prize waiting for you underneath is full-blown depression?
It is a question, of course, of degree: how significant are the effects of someone's chosen "mask". Maybe its burden has become too high a price to pay, preventing the finding of fulfilling work; or a successful relationship; or a sense of balance; or just a moment's peace.
Only by dealing with underlying depressive feelings will the mind be freed from clinging to its old patterns for warding them off. If latent depression is acknowledged and faced up to there is the potential to live in a fuller, richer, more meaningful way. For if depression is not just about a set of particular symptoms but is actually emotional - and psychic - deadness, the possibility held out by change is no less than life.
After a depression it takes a long time to feel truly alive again, and I learned that your life may change quite fundamentally in the process. I am newly back in London, busy setting up my own therapy practice, which will provide treatment for a wide range of emotional and psychological problems, including depression, anxiety, addiction and intimacy issues. It is a far cry from the Westminster and Soho high life.
I haven't taken antidepressants for the past year and so far have yet to slide back into depression, though on certain days I am conscious of it hovering over me, like a ghost. To make sure it stays exorcised I still see someone - I'm currently undergoing psychoanalysis, which is a deeper, more frequent form of therapy. I want to be sure that as well as avoiding depression's blatant manifestation I keep its more latent forms at bay too.