( CNN ) -- The poet Sylvia Plath , who made a name for herself through prose and poetry that conveyed a sense of depression and suicidal tendencies , famously died by asphyxiating herself in an oven in 1963 . There is evidence that depression runs in families , but both genetics and environment influence the condition . The recent reported suicide of her son , marine biologist Nicholas Hughes , brings to light a known psychiatric phenomenon : the heredity of suicidal behavior . A first-degree relative -- a parent , sibling or child -- of a person who has committed suicide is four to six times more likely to attempt or complete a suicide , said Dr. David Brent , psychiatrist at the University of Pittsburgh Medical Center . Studies on twins have shown that suicidal behavior is between 30 and 50 percent due to heritable factors , he said . Suicide victims ' biological relatives who were adopted away also show an increased risk of suicide , he said . The rate of suicide in America is 10.9 suicide deaths per 100,000 people , according to the latest information from the National Institute of Mental Health . That means , although the likelihood of suicidal behavior increases in families , a completed suicide is still a rare event , Brent said . `` Genetics is not destiny , '' he said . `` The odds are still very much against you having this happening to another relative . '' Family history of suicide and family history of mental disorder are two risk factors that the National Institute of Mental Health lists . More than 90 percent of people who die by suicide have depression or another mental disorder , or a substance abuse disorder in combination with another mental problem , according to the National Institute of Mental Health . Learn about the link between depression and creativity . Research shows that depression runs in families . A new study in the Proceedings of the National Academy of Sciences shows biological markers for the inherited condition . The researchers found , in a sample of 131 people , that the biological offspring of depressed people had structural differences in their brain . Some of these people had been followed for more than 25 years . Learn more about mood disorders » . People at high risk of developing depression had a 28 percent thinning of the right cortex , the brain 's outermost surface , the study found . Those with an extra thinning abnormality in the left cortex were most likely to develop depression or anxiety . The data set shows that this brain surface thinning was present before these people developed mental problems , and was found in both children and grandchildren of depressed people , said Dr. Bradley Peterson , psychiatrist at Columbia University Medical Center and co-author of the study . The new study may point toward more individualized medicine -- one day people may be screened for these brain abnormalities that indicate high depression risk , and receive treatment based on that , he said . Researchers believe the cortical thinning causes depression by interfering with the processing of emotional stimuli , he said . A person with these brain abnormalities may benefit from therapy targeted at responding to social stimuli more appropriately , he said . With both depression and suicide , research suggests that causal factors are a combination of genetics and environment , Peterson said . The best way to prevent suicide is to treat the underlying psychiatric disorder , Brent said . Besides Hughes and Plath , famous examples of two or more close relatives committing suicide include Ernest Hemingway 's family -- Hemingway 's father , brother , sister and granddaughter , in addition to the famous novelist himself , killed themselves . The poet John Berryman jumped off a Minneapolis bridge in 1972 ; his father had committed suicide when the poet was a child . More recently , the playwright Spalding Gray apparently killed himself in 2004 ; his mother had taken her own life many years earlier . Do relatives of people who killed themselves imitate suicide ? This is possible , but hard to prove or disprove , Brent said . In fact , there is more evidence of copycat suicides among people who did not know the victim well , but merely learned about him or her through the news . If you 've actually lost a relative to suicide and go through the bereavement process , you may be more likely to understand the aftermath of suicide , Brent said . Suicide `` can also represent the learned or transmitted way of coping with unbearable stress , '' Peterson said . What exactly gets transmitted in families with suicide ? One theory is that it 's a difficulty in emotional regulation . `` Not necessarily depression per se , but it 's the ability to restrain yourself from acting on suicidal thoughts , '' Brent said . The American Association of Suicidology is one place for online information if you or someone you know is contemplating suicide . For immediate assistance , contact the National Suicide Prevention Lifeline at 1-800-273-TALK ( 8255 ) .
First-degree relatives are 4 to 6 times more likely to attempt or complete a suicide . Still , says expert , `` genetics is not destiny '' it's the result of many factors that can be controlled by parents and other family members. Ernest Hemingway committed suicide , and so did several of his relatives .