Methods people used to kill themselves changed over time, dependent largely on availability.
In the 19th and early 20th centuries the most common method of suicide was poisoning. In Auckland before 1939 almost a quarter of suicides died this way. Poisoning was favoured by women, who had easy access to poisonous household disinfectants like Lysol (used for cleaning baths and drains) and to phosphorous matches.
Poisons were also available on the farm, where strychnine, cyanide and arsenic were used against rabbits and other pests. Between 1890 and 1950 almost one in five male suicide victims poisoned themselves. While most 19th-century poisonings were by liquids or solids, the arrival of reticulated domestic gas changed the situation. Less than 4% killed themselves by gassing in Auckland in the 1910s, but by the 1920s the numbers had rocketed to more than 26%.
For men the most popular means of suicide was firearms. In rural areas guns were readily to hand for hunting. Until 1920 over a quarter of suicides shot themselves. As society became more urban, shootings declined, but remained the leading method for men – although not for women. From the 1930s until about 1960 shooting was nearly always the most common method of suicide.
The next most popular methods were hanging and drowning. Both ranged between 10% and 20% of suicides before 1939. However, suicide by drowning was often difficult to distinguish from accidental death.
Since most men carried a razor for shaving, cutting was more popular among men than women. In 1890–1950, 12% died that way.
Jumping from high places was much less common, except in Auckland where Grafton bridge was a favoured location for suicides.
During the 1960s and 1970s poisoning by solid or liquid substances became the favoured method. Many were overdoses of pills. From 1979, as the number of suicides began to rise among the young, both hanging and poisoning by carbon monoxide from car fumes increased dramatically. Shooting and other poisoning declined.
By 2008 over half of suicides, both male and female, hanged themselves. This method was especially favoured by young people and by Māori (78% of suicides by Māori in 2005), and was common in prison, where few other methods were possible. Poisoning by car-exhaust fumes had declined from 28% in 1997 to 14.1% in 2008 – partly because imported cars were required to be fitted with catalytic converters which prevented poisoning. Under 10% of suicide victims shot or poisoned themselves with solids or liquids. The reduction in shooting was partly because the Arms Act 1983 and the Arms Regulations 1992 had restricted access to guns, and the reduction in poisoning was helped by restricting the availability of drugs and allowing paracetamol to be sold only in smaller amounts. However, in 2008 81% of admissions to hospital for attempted suicides by women were cases of self-poisoning. The erection of barriers at well-known jumping spots was also effective in keeping that cause of death low.
Time and place
Since the 19th century in New Zealand, as in other western countries, spring has been the most common time for suicides.
Women were much more likely to kill themselves in their own homes, while up to a third of male suicides did it in public places or buildings.