The New Black, By Darian Leader

In his great, digressive encyclopaedia of the human condition, The Anatomy of Melancholy, Robert Burton noted that melancholy is the very "character of mortality". Three centuries later, in a brief but resonant essay, Freud teased out the links between mourning and melancholia and placed loss at the centre of the experience that makes each one of us who we are. Today, when happiness seems to be the point both of life and government reports, depression – the clinical category that has swallowed up melancholy – is everywhere. By 2010, the World Health Organization predicts, depression will have become the single largest public health problem after heart disease.

While it colonises our many forms of unhappiness, depression has also come to be understood as an "organic" illness and thus susceptible to quick cure. Big Pharma, our third most profitable industry, has the necessary pills to hand, as well as the publicity, often enough in the form of "scientific" reports which convince the medical profession of their drugs' efficiency. Alongside many types of anti-depressants, we now also have a supposedly efficacious treatment in CBT (Cognitive Behaviour Therapy), that handy mixture of positive thinking and mind control soon to be available to all on the NHS.

Psychoanalyst Darian Leader isn't convinced, either by the current behaviour-based descriptions of depression, diagnosed according to a check-list of factors that drugs can shift (appetite, mood, and sleep patterns) or by the cures. People, he shows us in this taut new book, are both more complicated and far more interesting. Leader has grown into a fine writer, one who can untangle the complexities of the great psychoanalytic thinkers – Freud, Klein and the notoriously difficult Lacan – and turn them into the more common sense that the English language demands, while dipping into contemporary culture, high and low. Depression, he argues, is not just a set of pre-ordained symptoms, but as "multiple and varied as those who are told they suffer from it".

Its source can lie deeply buried in an individual's history and far from present awareness, though the trigger may well be a separation or crisis. At its core is the experience of loss: engaging in the difficult process of mourning is what allows us to come through.

Among the many cases in this book, he presents a young woman who fell into a deep depression when her wish to move in with her transatlantic boyfriend was finally fulfilled. Desire left the relationship. Only years later in her analysis did it come clear that the sustaining force of the twosome had been the distance between them. This allowed her to stage "one hundred goodbyes" every time they met. She was effectively making good the parting she had never been able to make from her father, who had died when she was 14 without her taking appropriate leave.

His fatal condition had been kept from her and his death had come as a terrible shock. Her inability to digest her mourning had worked itself into the much later love affair, the failure of which had resulted in depression.

Leader's analysis of the work of mourning – its pitfalls, the blockages it can produce – is exemplary. He highlights the recognition of a necessary hatred alongside love for the lost one, the identification with the person so that our reproaches of them are converted into self-reproach, the need to frame the space they occupied for us, and then give up who we were for them. Drawing on anthropological sources, he underscores the importance of a public recognition of mourning, too often lacking today. One facet of experience Leader doesn't contend with here is religion, surely a player for Lacan.

If in mourning, we grieve the dead and ourselves in them, in severe depressive illness we die with them. A sense of loss engulfs them and us in a black hole. Is there a way of navigating that acute sense of deadness to emerge alive? Leader finds a possible answer in language and representation: "to find words to say how words fail". This he designates as the very task of poetry.

Leader's passion for the inner life makes him particularly susceptible to literature and art. Among much else, he provides a subtle commentary on some of our leading conceptual artists: Cornelia Parker, Rachel Whiteread, Bruce Naumann, Sophie Calle figure prominently.

The making of art, poetry and literature, Leader argues, often arises from an attempt to give presence to the absence which underlies mourning and the all-too-human condition of melancholy. This may well be part of the acknowledged "therapeutic" value of reading. There are many self-help books on the market. Though not advertised as one, The New Black is a book that might actually help.

Lisa Appignanesi's 'Mad, Bad and Sad: A history of women and the mind doctors from 1800' is published by Virago next month

Hamish Hamilton £17.99 (230pp) £16.29 (free p&p) from 0870 079 8897