Suicide
Suicide is the act of intentionally causing one's own death.[9] Mental disorders (including depression, bipolar disorder, schizophrenia, personality disorders, anxiety disorders, attention deficit hyperactivity disorder, cognitive disengagement syndrome), physical disorders (such as chronic fatigue syndrome), and substance abuse (including alcoholism and the use of and withdrawal from benzodiazepines) are risk factors.[2][3][5][10] Some suicides are impulsive acts due to stress (such as from financial or academic difficulties), relationship problems (such as breakups or divorces), or harassment and bullying.[2][11][12] Those who have previously attempted suicide are at a higher risk for future attempts.[2] Effective suicide prevention efforts include limiting access to methods of suicide such as firearms, drugs, and poisons; treating mental disorders and substance abuse; careful media reporting about suicide; improving economic conditions;[2][13] and dialectical behaviour therapy (DBT).[14] Although crisis hotlines are common resources, their effectiveness has not been well studied.[15][16]
For information on prevention, see Suicide prevention. For other uses, see Suicide (disambiguation).
The most commonly adopted method of suicide varies from country to country and is partly related to the availability of effective means.[17] Common methods of suicide include hanging, pesticide poisoning, and firearms.[2][18] Suicides resulted in 828,000 deaths globally in 2015, an increase from 712,000 deaths in 1990.[19][20] This makes suicide the 10th leading cause of death worldwide.[3][6]
Approximately 1.5% of all deaths worldwide are by suicide.[8] In a given year, this is roughly 12 per 100,000 people.[6] Rates of suicide are generally higher among men than women, ranging from 1.5 times higher in the developing world to 3.5 times higher in the developed world.[1] Suicide is generally most common among those over the age of 70; however, in certain countries, those aged between 15 and 30 are at the highest risk.[1] Europe had the highest rates of suicide by region in 2015.[21] There are an estimated 10 to 20 million non-fatal attempted suicides every year.[22] Non-fatal suicide attempts may lead to injury and long-term disabilities.[23] In the Western world, attempts are more common among young people and women.[23]
Views on suicide have been influenced by broad existential themes such as religion, honor, and the meaning of life.[24][25] The Abrahamic religions traditionally consider suicide as an offense towards God due to belief in the sanctity of life.[26] During the samurai era in Japan, a form of suicide known as seppuku (腹切り, harakiri) was respected as a means of making up for failure or as a form of protest.[27] Similarly, a ritual fast unto death, known as Vatakkiruttal (Tamil: வடக்கிருத்தல், Vaṭakkiruttal, 'fasting facing north'), was a Tamil ritual suicide in ancient India during the Sangam age.[28] Suicide and attempted suicide, while previously illegal, are no longer so in most Western countries.[29] It remains a criminal offense in some countries.[30] In the 20th and 21st centuries, suicide has been used on rare occasions as a form of protest; it may also be committed while or after murdering others, such as suicide attacks which have been used as both a military and terrorist tactic.[31] Suicide is often seen as a major catastrophe causing significant grief to the deceased's relatives, friends and community members, and it is viewed negatively almost everywhere around the world.[32][33][34]
Pathophysiology
There is no known unifying underlying pathophysiology for suicide;[23] it is believed to result from an interplay of behavioral, socio-economic and psychological factors.[17]
Low levels of brain-derived neurotrophic factor (BDNF) are both directly associated with suicide[169] and indirectly associated through its role in major depression, post-traumatic stress disorder, schizophrenia and obsessive–compulsive disorder.[170] Post-mortem studies have found reduced levels of BDNF in the hippocampus and prefrontal cortex, in those with and without psychiatric conditions.[171] Serotonin, a brain neurotransmitter, is believed to be low in those who die by suicide.[172] This is partly based on evidence of increased levels of 5-HT2A receptors found after death.[173] Other evidence includes reduced levels of a breakdown product of serotonin, 5-hydroxyindoleacetic acid, in the cerebral spinal fluid.[174] However, direct evidence is hard to obtain.[173] Epigenetics, the study of changes in genetic expression in response to environmental factors which do not alter the underlying DNA, is also believed to play a role in determining suicide risk.[175]
![Death rate from suicide per 100,000 as of 2017[208]](http://upload.wikimedia.org/wikipedia/commons/thumb/0/01/Death_rate_from_suicides_%28IHME_%281990_to_2016%29%29%2C_OWID.svg/312px-Death_rate_from_suicides_%28IHME_%281990_to_2016%29%29%2C_OWID.svg.png)
![Share of deaths from suicide, 2017[209]](http://upload.wikimedia.org/wikipedia/commons/thumb/6/6a/Share_of_deaths_from_suicide%2C_OWID.svg/312px-Share_of_deaths_from_suicide%2C_OWID.svg.png)