We are living longer now than ever before; but for many people, old age brings a despair so total that they prefer to die a violent, lonely death at their own hand.

The suicide rate among people over 80 is about 100 per million - the highest of all age groups. And while younger people bent on suicide may turn to drugs, the elderly use more violent methods.

Dr Peter Jefferys, a consultant in old age psychiatry at Northwick Park Hospital, Harrow, has compiled a national geriatric 'suicide audit' which reveals that elderly men are more likely to die by hanging, shooting and drowning than younger groups.

'People who are depressed are often angry with themselves, the world and those around them,' he points out. 'The older generation was brought up during the First and Second World Wars, and people didn't take drugs then. If you were a man you didn't quietly go away and die; you demonstrated that what you were doing was killing yourself - by hanging, by drowning. This was the macho way of showing what you really felt.'

People with severe depression, particularly as they get older, also feel that they deserve to be punished: that they are a liability to the world. 'These feelings of guilt and unworthiness reach such an intensity that people feel the world would really be relieved if they were no longer alive,' Dr Jefferys says.

Dr David Jolley, a geriatric psychiatrist at the Withington Hospital, south Manchester, believes that one reason for the 'extraordinary' number of hangings by elderly men is its historical associations with punishment. 'It is a form of self-judgement - using what was once the legal means for exterminating people,' he says. Research shows that 80 per cent of old people who commit suicide are depressed, and half of these will have made contact with their doctor shortly before committing suicide.

Suicide by drug overdose is often unacknowledged in the elderly. Dr John Kellett, a senior lecturer in psychiatry in geriatric medicine at St George's Hospital, London, argues that the rate of geriatric suicide by this method is higher than statistics show.

'It's convenient for post-mortems to give the cause of death as heart attack rather than drug overdose: you can always find traces of artery disease in old people,' he says.

The tragedy is that many of the depressive disorders that lead to suicide in the elderly are treatable, but often the patient is dismissed as being old, or incorrectly diagnosed as suffering from dementia.

With the number of old age pensioners predicted to rise from just over 10 million today to nearly 15 million in the next 40 years, specialists believe that the problem of geriatric suicide needs to be tackled fast.

Dr Jolley, who is also chairman of the interest section for old age psychiatry at the Royal College of Psychiatrists, argues that if health and social service provisions do not keep pace with the growing elderly population, suicide rates will spiral: 'If we don't put resources into improving the quality of life of elderly people, in effect we will be trying to bump them off early.'

He is particularly dismayed by the Government's decision to exclude the over-65s in its nationwide mental health survey, part of the much- publicised Health of the Nation White Paper published in 1992 by the Department of Health. The DoH maintains it already has information on mental disorders in the elderly from the Medical Research Council.

Dr Jolley also warns that if the Government deregulates residential care homes the problem will be swept under the carpet. With increased demand for places in care homes, he says, there is an even greater need to provide trained carers who can help those at risk from suicide.

Dr Jefferys' findings show that, unlike other groups, suicide rates among the elderly are not highest in inner- city areas. Well-off areas such as Hampstead in north-west London have a far greater number of geriatric suicides than deprived inner-city districts such as Tower Hamlets.

In the United States, the rate of suicide among elderly black and Indian males is far lower than among their more prosperous white counterparts. And in India the risk of suicide actually declines with age, as it does with Indians living in the UK. Psychologists believe that this is due to the high esteem in which the elderly are held in these communities.