Genetic Link to Suicide: BDNF Marker Val66Met

By

Home / Genetic Link to Suicide: BDNF Marker Val66Met

Despair: Image by Andrea Silva

The tragedy of suicide has a ripple effect, traumatizing those left behind and sometimes creating a contagion effect, especially among adolescents and young adults.  Studies have revealed various risk factors for suicide, with alcohol dependency standing out as a major factor.  The risk for suicidal ideation and completion is increased 60 to 120 times in those dependent on alcohol.  This relationship is a complex one, with genetics and mood disorders influencing alcohol use and alcohol exacerbating pre-existing depression and impulsivity.  Self-medication with alcohol and street drugs (including prescription drugs) is common among those with untreated trauma and mood disorders.

Genetic Factors in Suicide?

Neuropsychologists have extensively researched links and interactions among variables related to suicide, and there are no simple answers.   Acknowledging the complexity of individual differences and multiple influences on suicidal behaviour, a group of Canadian and Italian scientists recently collaborated on a meta-analysis of 12 studies of suicidal behaviour.  Their conclusions were presented in the International Journal of Neuropsychopharmacology.

This meta-analysis was the first to examine the role of the functional BDNF marker Val66Met (Brain Derived Neurotrophic Factor), which acts on retinal, cholinergic, dopaminergic, motor and sensory neurons.  3352 participants were included in this study, with 1202 participants having a history of suicidal behaviour.  Researchers concluded that there was a trend for the Met-carrying genotypes and Met allele increasing risk for suicidal behaviour, although further research is required in order to determine how BDNFVal66 influences suicidality.

Suicidal behaviour is apparently contrary to biological evolution.  Various theories exist to explain this behaviour among humans,  including the idea that learning and belief systems can overwhelm innate drives such as procreation.  Evidence is that suicide occurs among people unable to reproduce or be productive, or who have distorted self-referencing beliefs regarding their self-worth or ability to be productive.  Impulsivity increases the chance of the individual taking action in response to these negative beliefs and emotional distress that accompany them.

Society and Suicide

Is there a genetic link to suicide? Image by Delaware Biotechnology Institute

Prior to the influence of Christian doctrine, in ancient times, suicide was often considered a rational act, subject to a complex moral decision-making model.  Subsequently, and until the early 1960’s, suicide was considered a criminal act, and lawyers worked to avoid punitive consequences for the suicidal person.  This led to the formula “when the balance of the mind is disturbed.” – created in a effort to explain the behaviour without criminalizing the distressed person.

In recent times, suicidal thinking and behaviour is recognized as a social and psychological problem that has tragic results.  The World Health Organization states that those most vulnerable to suicide are:

  • Young males (aged 15-49)
  • Elderly people, especially male
  • Indigenous people
  • Mentally ill individuals
  • Those with alcohol and or substance/abuse
  • Those with a history of suicide attempts
  • Persons in custody

Reliable information and support is easily accessible.  Online, suicide prevention information can be accessed at HelpGuide, and most communities have 24 hour help lines for immediate support.

Sources

Clement C. Zai, Mirko Manchia, Vincenzo De Luca, Arun K. Tiwari, Nabilah I. Chowdhury, Gwyneth C. Zai, Ryan P. Tong, Zeynep Yilmaz, Sajid A. Shaikh, John Strauss and James L. Kennedy The brain-derived neurotrophic factor gene in suicidal behaviour: a meta-analysis. The International Journal of Neuropsychopharmacology, Available on CJO 2011 doi:10.1017/S1461145711001313

L. Sher.  Alcohol Consumption and Suicide.  University of Oxford Press.  2005.

Denys deCatanzaro.  Human Suicide:  A Biological Perspective.  Behavioural and Brain Sciences, Volume 3, Issue 2 pp 265 – 272. Published online: 04 February 2010

Medicine and Moral Reasoning.  Ed. K.W.M. Fulford, G. Gillett, J. M. Soskice.  Online publication, April, 2011. Accessed October 8, 2011.

Leave a Comment