Methods people used to kill themselves change over time, largely on the basis of knowledge of and access to different ways of dying.
In the 19th and early 20th centuries the most common method of suicide was taking poison. In Auckland before 1939 this accounted for almost a quarter of suicides. Poison was often chosen by women, who had easy access to 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. Fewer than 4% of Auckland suicides killed themselves by gassing in the 1910s, but in the 1920s the proportion rocketed to 26%.
For men the most frequent means of suicide was firearms. In rural areas guns were readily to hand for hunting. Until 1920 more than a quarter of suicides shot themselves. As society became more urban, shootings declined, but this remained the leading method for men. From the 1930s until about 1960 shooting was the most common method of suicide.
The next most common methods were hanging and drowning, which each accounted for between 10% and 20% of suicides before 1940. However, suicide by drowning was often difficult to distinguish from accidental death.
Since most men possessed a razor for shaving, cutting was a more common method for men than for women. Between 1890 and 1950, 12% of male suicides died that way.
Jumping from high places was much less common, except in Auckland where Grafton bridge was a common location for such suicides. After safety barriers on the bridge were demolished in 1996, the number of suicides by jumping from the bridge increased. New tempered glass barriers were installed in 2003.
During the 1960s and 1970s, poisoning by solid or liquid substances became a more common method of suicide. Many were overdoses of pills. From 1979, as the number of suicides among the young began to rise, hanging and poisoning by carbon monoxide from car fumes increased dramatically. Shooting and other forms of poisoning declined.
In 2015, 62% of suicides, both male and female, were deaths by hanging, strangulation or suffocation. This method was especially used by young people (83%) and Māori (90% of suicides), and was common in prison, where few other methods were feasible. Poisoning by car-exhaust fumes had declined from 28% in 1997 to 9% in 2008 – partly because imported cars were required to be fitted with catalytic converters which prevented poisoning. Fewer than 10% of suicide victims shot or poisoned themselves. 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 restrictions on the availability of drugs. The erection of barriers at well-known jumping spots was also effective in reducing that cause of death.
Time and place
Since the 19th century in New Zealand, as in other western countries, spring has been the most common season for suicides.
Women are much more likely to kill themselves in their own homes, while up to a third of male suicides occur in public places or buildings.