Suicide methods can be classified according to two modes of interrupting life processes: physical or chemical. Physical modes of interruption typically act by incapacitating the respiratory system or the central nervous system, usually by destruction of one or more key components. Chemical modes focus on interrupting biologically significant processes such as inhibition of cellular respiration or reduction of diffusion capacity. Chemical methods of suicide produce latent evidence of action, while physical methods provide direct evidence.
It was also practiced as a ritual suicide method in Japan called jigai, by noble women for the same purposes as seppuku was used by men.
Suicide by drowning is the act of deliberately submerging oneself in water or other liquid and staying there long enough to prevent breathing and deprive the brain of oxygen. Due to the body's natural tendency to come up for air, drowning attempts often involve a heavy object, to circumvent this reflex. If the drowning is stopped before death, oxygen deprivation can cause brain damage. Drowning oneself is not often used.
When explosives are detonated with the intent of also harming others in close proximity it is commonly known as a suicide bombing.
Hanging is the prevalent means of suicide in pre-industrial societies and is still more common in rural rather than urban areas.
The traditional death penalty of hanging by gallows consists of a rope tied to a fixed object (i.e. the gallows), with one end tied into a hangman's noose and placed around the neck. The person falls through the release of a trap door (or leaps from a height, in the case of suicide), and death is instantaneous due to breaking of the neck.
Jumping in front of an underground train is a common form of suicide in London. Where a deep drainage pit is present, this halves the likelihood of fatality. Separation of the passengers from the track by means of a partition with sliding-doors is being introduced in some stations but this is expensive.
The real percentage of suicides among car accidents is not reliably known; studies by suicide researchers tell that "vehicular fatalities that are suicides vary from 1.6% to 5%".. Some suicides are misclassified as accidents because suicide must be proven. "It is noteworthy that even when suicide is strongly suspected but a suicide note is not found, the case will be classified 'accident.'"
Some researchers believe that suicides disguised as traffic accidents are far more prevalent than previously thought. One large-scale community survey among suicidal persons provided the following numbers: "Of those who reported planning a suicide, 14.8% (19.1% of male planners and 11.8% of female planners) had conceived to have a motor vehicle “accident”... Of all attempters, 8.3% (13.3% of male attempters) had previously attempted via motor vehicle collision.
The 70 m (225 ft) plunge from the Golden Gate Bridge has proven to be fatal in 98% of cases. The jumper would hit the water at 120 km/h (about 75 mph). Most die of internal bleeding due to broken ribs which pierce the heart, lungs, liver or spleen. Survivors, who generally have hit the water feet-first, have often had their femurs shattered.
Authorities have tried to prevent jumping suicides by building fences or other barriers in potential areas, such as high towers and bridges. In some areas authorities have also installed telephones which link directly to suicide prevention hot lines. , a term that is applied specifically to falling from a window opening.
Assisted suicide group Dignitas reported that there was no single failure among 840 cases, where an overdose of a former sleeping pill active agent Nembutal was used. While barbiturate (like Seconal or Nembutal) are considered a safe option for suicide, it is becoming increasingly difficult to acquire these drugs. Today they are only available as a dilution and are used by veterinarians to kill animals.
However, a typical drug overdose uses random prescription and over-the-counter substances. In this case death is uncertain, and an attempt may leave a person alive but with severe organ damage, which may prove eventually fatal itself. Drugs taken orally may also be vomited back out before being absorbed. Considering the very high doses needed, vomiting or falling asleep before taking enough of the active agent might be a serious hurdle.
Analgesic overdose attempts are among the most common due to easy availability of over-the-counter substances. Overdosing may also be performed by mixing medications in a cocktail with one another, or with alcohol or illegal drugs. This method may leave confusion over whether the death was a suicide or accidental, especially when alcohol or other judgment-impairing substances are also involved and no suicide note was left behind.
Carbon monoxide is a colorless and odorless gas, so its presence cannot be detected by sight or smell. It is harmful to humans since the CO molecules attach themselves to hemoglobin in the blood, displacing oxygen molecules and progressively lowering the body's oxygenation, eventually resulting in death.
In the past, before air-quality regulations and catalytic converters, suicide by carbon monoxide poisoning would often be achieved by running a car's engine in a closed space such as a garage, or by redirecting a running car's exhaust back inside the cabin with a hose. Motor car exhaust may have contained up to 25% carbon monoxide. However, catalytic converters can eliminate over 99% of carbon monoxide produced.
The incidence of suicide by carbon monoxide poisoning through burning charcoal, such as a barbecue in a sealed room, appears to have risen. This has been referred by some as "death by hibachi".
Unlike other methods of suicide, this was regarded as a way of preserving one's honor. The ritual is part of bushido, the code of the Samurai.
Dressed ceremonially, with his sword placed in front of him and sometimes seated on special cloth, the warrior would prepare for death by writing a death poem. With a selected attendant (kaishakunin, his second) standing by, he would open his kimono, take up his wakizashi (short sword), fan, or a tanto (knife) and plunge it into his abdomen, making first a left-to-right cut and then a second slightly upward stroke. On the second stroke, the kaishakunin would perform daki-kubi, when the warrior is all but decapitated, leaving a slight band of flesh attaching the head to the body, so as to not let the head fall off the body and roll on the floor/ground; which was considered dishonorable in feudal Japan.
Starvation has been used by Hindu, Jain and Buddhist monks as a ritual method of suicide.
Such attacks are typically motivated by religious or political ideologies and have been carried out using numerous methods. For example, attackers might attach explosives directly to their bodies before detonating themselves close to their target, or they may use car bombs or other machinery to cause maximum damage (e.g. Japanese kamikaze pilots during World War II).
Islamic extremist terrorists have engaged in suicide attacks numerous times in the Arab-Israeli conflict, and also against the West at other times. Perpetrators believe the gains to others, or to a religious, political or moral cause, outweigh their personal loss and/or that they will be rewarded in the afterlife.
Additionally, teenage students (most often in the United States of America and recently in Finland) have committed several notable suicide attacks in recent years, in the form of school shooting massacres. Often, these suicide attacks involve guns or homemade bombs brought into high schools or college campuses. After the attack, the perpetrator will commit suicide before being apprehended.
1993, 68 pages