More women and people suffering from non-fatal illnesses are opting for assisted suicide, a study on Swiss right-to-die organisations has found.
The researchers also identified "weariness of life rather than a fatal or hopeless medical condition" as an increasingly common reason for older people to commit suicide in this way.
One of the two organisations studied, Exit Deutsche Schweiz, which deals mainly with Swiss residents, has criticised the findings as unrepresentative, pointing out that the data for the Zurich area only refers to a third of its cases.
The research team from Zurich University analysed official records of such deaths in Zurich from 2001 to 2004.
Women accounted for two-thirds of all cases, with the largest group aged between 65 and 84. One in four of all patients were suffering from non-fatal illnesses, while the most common terminal illnesses were cancer and neurological diseases. Three per cent of those who were helped to die were suffering from a mental disorder.
"If you compare the results for Exit Deutsche Schweiz in Zurich... with the 1990s there is an increase in elderly people, in people not suffering from a fatal disease and in women," Georg Bosshard, who led the research, told swissinfo.
"So there is definitely a shift in this field and we must have a discussion about it."
The study looked at the profile of 274 people assisted to die by Dignitas, more than 90 per cent of whom came to Switzerland from abroad, and 147 almost exclusively Swiss residents helped to commit suicide by Exit.
The most common country of origin of non-Swiss individuals was Germany, making up two thirds of Dignitas' patients. The next largest nationality was British at eight per cent (23 people in the period studied), followed by French at seven per cent.
Switzerland has a growing international reputation as a destination for assisted suicide. Individual stories regularly make the headlines in Britain, one recent case being Daniel James, who travelled to Zurich to die in September. The 23-year-old was paralysed in a rugby accident.
Also in Britain, a woman with multiple sclerosis lost her High Court case to clarify the law on assisted suicide last month. Debbie Purdy, who is considering going to Switzerland to end her life with Dignitas, fears her husband may be charged on his return to the UK.
She had wanted a guarantee that her husband would not be prosecuted. There have so far been no prosecutions of the relatives of 101 British citizens who have ended their lives with the help of Dignitas.
The four right-to-die organisations active in Switzerland have similar preconditions for those who want to die. The service is only offered - after an evaluation process - to those demonstrating a deliberate and stable wish to die, sufferers of a disease with a hopeless prognosis, those undergoing unbearable suffering or in cases where unreasonable disability is present.
More women and elderly
As a possible explanation for the over-representation of women in assisted suicide, the study authors say women tend to verbalise their feelings and seek help more than men. Men are also more likely to take their own lives alone.
It is also a question of numbers. More women than men suffer from depression and there are more women in older age groups due to their longer life expectancy. But the Swiss system also shows signs of being "softer" on women and the elderly compared with doctor-dominated systems elsewhere.
In The Netherlands more women request assistance in dying but are more likely to have their requests refused, particularly as doctors often find signs of depression. The end result is that there is no significant difference between the sexes in facilitated suicide numbers.
"Most doctors and medical associations feel that there is a tension between the role of a doctor and the role of a person who assists in the death by suicide of the patient," Bosshard said.
Swiss doctors are involved in the diagnosis and prognosis and in informing the patient about treatment options and palliative care, he added. Meanwhile it is representatives of the right-to-die organisation who provide guidance and are present for the suicide.
Compared with The Netherlands where doctors control assisted dying, the study concluded that assistance for older people who were not suffering from a terminal illness was also more readily available in Switzerland.
"It is known from studies on end-of-life decisions in The Netherlands that doctors quite often receive requests for assisted dying from people aged 80 years and over who are not suffering from a terminal illness. Dutch doctors ... almost never grant such requests," the authors note.
"In a system where right-to-die organisations play an important role, assistance for older people in dying appears to be considered as showing respect for their self-determination."
swissinfo, Clare O'Dea
Based on article 115 of the Swiss Penal Code, Swiss right-to-die organisations can legally offer aid in dying.
The way of committing suicide is usually with a lethal dose of barbituates that has been prescribed by a doctor.
The Swiss practice of assisted suicide allows assistance in dying using intravenous drips or stomach tubes.
The legally critical act is the last step of the procedure, opening the tap of the drip or tube.
The last step must always be carried out by the individual wanting to die and this must be attested to by a witness.
This study is based on an analysis of all reported assisted suicides in Zurich from 2001 to 2004. There were 421 deaths, of which:
44 years and under: 6.9%
Aged 45-64: 33.3%
Aged 65-84: 43.9%
85 years and over: 15.9%
Swiss residents: 39.4%
Non-resident in Switzerland: 60.6%
Countries of origin: Germany (43%), Great Britain (8%), France (7%),
Type of diagnosis: Fatal illness (74.8%), Non-fatal illness (24.9%)
Assisted suicide in Europe
Switzerland: Assisted suicide and passive euthanasia is legal. Active euthanasia is illegal.
Germany and Italy: Assisted suicide is illegal.
France: Passive euthanasia by doctors or relatives will be legal in future. Active euthanasia remains illegal.
Netherlands and Belgium: permit taking the life of a person who wishes to die.
Britain: has the strictest regulations against assisted suicide in Europe. Many Britons come to Switzerland.