[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]
With the recent suicide of Nicholas Hughes we are tempted to think there might be heritability in taking one’s life. Since his mother, the poet Sylvia Plath, stuck her head in a gas oven a year after he was born.
A 2005 longitudinal study published in the American Journal of Psychiatry showed that children of mothers who attempted suicide were significantly more at risk of suicide than children of mothers who were not suicidal.
And a 2003 study in the same journal concluded from a Swedish survey that the rate of suicide is twice as high in families of suicide victims than in families with no suicide.
But such studies show correlation, not causal connection.
And while a 2007 review from The Middle-European Journal of Medicine concludes that suicide is significantly more frequent among identical twins versus fraternal twins, pinpointing the genetic link is difficult.
One problem is distinguishing genes associated with suicide from those associated with suicide-related mental illness. But a 2009 paper in Biological Psychiatry proposes that the suicidal traits that may be genetically-linked are aggression and impulsivity, early-onset depression and stress hormone levels.
Whether Hughes inherited a suicidal tendency is unknown. But he suffered from depression and had significant life trauma. Not only did his mother commit suicide, his father’s second lover, Assia Wevill, also committed suicide, by asphyxiation from a gas stove. Curiously, she died 40 years ago to the very day—when Hughes decided to take his own life.
NOTE: Other studies in the past year suggest that links to suicide may be due to a reduction in the number of receptors in the brain for the neurotransmitter GABA. Interestingly, the number of GABA receptors is not related to a genetic mutation, but is thought to be epigenetic, meaning the expression of genes is affected by life experience. For more on this study and further research on the causes of suicide, please see The Origins of Suicidal Brains.