“Timor mortis conturbat me” is a refrain that runs through medieval literature, like the memento mori, a reminder of “the skull beneath the skin”.

Its meaning is usually given as “the fear of death disturbs me” yet such existential angst can be elevated beyond the merely selfish. Most of us, after all, are filled with greater horror imagining the deaths of those we love. The contemplation of mortality, and grief, foresuffered and real, has been an inescapable part of the human condition since our ancestors shivered at howls in the impenetrable darkness.

It's not surprising, therefore, that a common response to loss (usually bereavement but often another sort, involving some colossal unexpected life change) is the arrival of the Black Dog. People speak of feeling “depressed” when they experience a temporary downturn in mood, or even the ennui of too much shopping and socialising, whereas depression as an illness signifies severe emotional disturbance.

Coleridge's great ode Dejection lists some recognisable symptoms (including separation from the world outside) but one could argue that being able to craft a disciplined work of genius from a personal crisis precludes genuine depression.

Darian Leader would agree that if a modern Coleridge went to his GP suffering from a bad marriage and creative block (not to mention the effects of all that self-medication) he would probably be told to “take the tablets” and join “Prozac nation”.

Considering the importance Freud attached to loss, it seems remarkable that psychiatrists took so long to recognise bereavement as an important cause of mental illness.

Leader aims, in his new book The New Black, to disentangle the idea of natural mourning from melancholia or pathological grief, to help “shed light on how we deal - or fail to deal with the losses that are part of human life”. He objects to the fact that the old distinction between mourning and melancholia made by Freud has been lost in the lazy, modern obsession with “depression”.

Right at the beginning he offers a crisp distinction: “In mourning we grieve the dead; in melancholia we die with them.” So in mourning one would say: I exist, without my father, and even though it pains me, I accept that separation. In melancholia one would say: I am nothing without my father and his loss is the whole of what I am.

Yet at a time when drug companies have a vested interest in promulgating the idea of an “illness” for which they can peddle a cure, and when people are more likely to seek medication than to endure suffering that must be worked through with patience, such distinctions are lost.

Leader's strictures are timely. In the 1970s it was normal for a woman enduring the grief of stillbirth to be prescribed tricyclic antidepressants, which effectively turned her into a zombie. Today a busy GP is likely to dish out drugs such as Seroxat to a patient with what analysis - “the talking cure” - would reveal as sorrow.

But Leader also objects to the ubiquity of the cognitive behavioural therapies popular with healthcare trusts. CBT, he says, is a too easy solution, viewing depression and mourning as isolated problems that can be treated regardless of context, such as the life history of the patient.

A practising psychoanalyst, he attacks - somewhat unfairly - mere cognitive behavioural therapists for treating depression as a symptom, not a cause. He is right to warn of quick fixes but surely wrong to suggest that only lengthy psychoanalysis can help. Even talking to a wise friend can, over time, help a mourner to detach from the dead. But yes, when the patient continues to be attached to the dead in a depressed, or melancholic state, more serious help is needed.

Leader's book begins well, is right to emphasise the importance of public mourning, but does not deliver all that it promises - especially on the issue of how the arts can be “a vital tool in allowing us to make sense of the losses inevitable in all of our lives”.

The New Black is, I regret to say, rather a catchpenny title for an old subject that is much richer and more complex than Leader acknowledges. For example, the distinction between melancholia and mourning is made to great effect in Jahan Ramazani's Poetry of Mourning (University of Chicago Press, 1994), offering a comprehensive account of “the modern elegy from Hardy to Heaney” which would have informed Leader's essay.

Ramazani makes the point that much poetry is “melancholic (in psychological terms) in that the impulse is not to achieve but to resist consolation... not to heal but to reopen the wounds of loss”.

This is what Elizabeth Bishop called “the art of losing” and Keats's Ode to Melancholy is one example, offering the beautiful, bleak truth that happiness and sorrow, love and loss must always coexist.

There is a vast literature of death and mourning of which Leader seems all but unaware. More than three centuries before Freud, Robert Burton, in The Anatomy of Melancholy (1621), wrote of “sorrow as a cause of melancholy” and gives countless examples of extravagant grief in ancient texts, from Plutarch to the Psalms. Burton writes that the death of friends is “so grievous a torment for the time that it takes away the appetite, desire of life, extinguishes all delights”.

Sadly, one cannot but contrast the turgid prose of the second half of The New Black (which reads like a hastily written academic paper) with the lucidity of the American undertaker-poet Thomas Lynch, who understands the melancholy truth of the lacrimae rerum, having experienced it at first hand: “But burying infants we bury the future, unwieldy and unknown, full of promise and possibilities, outcomes punctuated by our rosy hopes. The grief has no borders, no limits, no known ends and the little infant graves that edge the corners and fence-rows of every cemetery are never big enough to contain that grief. Some sadnesses are permanent. Dead babies do not give us memories. They give us dreams.”

Much as I would have liked Leader's insights to be bolstered by this creative hinterland (as promised) it is even more astonishing that he makes no reference to the work of Colin Murray Parkes, whose seminal Love and Loss: The Roots of Grief and its Complications (2006) manages to be both academic and written in prose that dances with love around its subject. Moreover, Parkes's ground-breaking Bereavement: Studies of Grief in Adult Life was published in 1972 and acknowledges a debt to John Bowlby's earlier work on loss. Naturally Parkes addresses issues of depression and atypical grief, yet Leader all but implies that this is an unploughed furrow. He must know of the debt to Parkes.

It's a pity, because The New Black contains the seeds of a much bigger, better work that would have built on the work of Parkes to reveal grief as an illuminator of the human condition, as well as its shadow.

The New Black: Mourning, Melancholia and Depression by Darian Leader
Hamish Hamilton, £17.99; 240pp

Times Recommends

• Extract: My Little Armalite
• Madonna: A life in 10 songs
• The Sunday Times 100 best holiday reads