Saturday, August 16, 2014

Genetic testing and suicide

Article: Could a Genetic Test Predict the Risk for Suicide?

A gene test would be invaluable to reducing suicide.
While claims for a suicide test remain preliminary, and controversial, a “suicide gene” is not as fanciful as it sounds. The chance that a person takes his or her own life is in fact heritable, and many scientific teams are now involved in broad expeditions across the human genome to locate suicide’s biological causes.

Based on such gene research, one startup company, Sundance Diagnostics, based in Boulder, Colorado, says it will begin offering a suicide risk test to doctors next month, but only in connection with patients taking antidepressant drugs like Prozac and Zoloft.

The Sundance test rests on research findings reported by the Max Planck Institute of Psychiatry in 2012. The German researchers, based in Munich, scanned the genes of 898 people taking antidepressants and identified 79 genetic markers they claimed together had a 91 percent probability of correctly predicting “suicidal ideation,” or imagining the act of suicide.
So, the first gene test is based on genetic markers. These would be the genes that can be passed on from parents to children. These genes would be part of the basis of the well-known familial risk factor (see below).
Given how many people take antidepressants, the market for a suicide test could be big. In the U.S., about 11 percent of Americans 12 years and older take antidepressants, according to a 2011 estimate by the U.S. Centers for Disease Control and Prevention.
People taking antidepressants have a higher risk of suicidal ideation and suicide. A test would help reduce the risk by identifying those prone to that and getting them counseling in advance of taking the drugs.
Altogether, epidemiologists believe that 30 percent to 55 percent of the risk that someone takes their own life is inherited, and the risk isn’t linked to any specific mental illness, like depression or schizophrenia.

That means suicide probably has its own unique genetic causes....
Oddly enough, a range 30-40% is the same for a lot of conditions that have a genetic linkage: mental illness and heart disease. Even the tendency towards homosexuality.
A person’s life history still has more to do with whether it ends in suicide than genes do. Virginia Willour, a geneticist at the University of Iowa who studies suicidal thinking among bipolar patients, says environmental factors are especially important in preventing suicide. Getting medical treatment, an involved family, and religious beliefs all cut the chance of suicide dramatically.
If 30-40% of the risk for suicide is genetic, then 60-70% of the risk is environmental factors.
The latest report of a possible suicide test came in July from Johns Hopkins University, in Baltimore, where geneticists published a report saying that the presence of alterations to a single gene could predict who will attempt suicide with 80 percent accuracy.

Instead of looking just at DNA, they studied patterns of methylation, a type of chemical block on genes that can lower their activity. They found that one gene, SKA2, seemed to be blocked often in the suicide brains. They later found the same gene block was common when they tested the blood of a larger number of people having suicidal thoughts.

“We seem to be able to predict suicidal behavior and attempts, based on seeing these epigenetic changes in the blood,” says Kaminsky.

Kaminsky says that following the report, his e-mail inbox was immediately flooded by people wanting the test. “They wanted to know, if my dad died from suicide, is my son at risk?” he says. They didn’t understand that the type of DNA change he identified probably isn’t the inherited kind, but instead may be the result of stress or some other environmental factor.
The second test used the DNA from the brains of suicide victims to see if there had been changes to their specific DNA. This would be changes due to environmental factors: chemical and hormonal exposure (including in the womb) or related to stress and life activities. This may account for some of the non-familial risk factors listed below. These changes may or may not be passed on. If they are changes in the brain, only, they will not be. To be passed on, the epigenetic changes would have to also happen in the sex cells (sperm and eggs).

Article: Suicide: Risk and Protective Factors
A combination of individual, relational, community, and societal factors contribute to the risk of suicide. Risk factors are those characteristics associated with suicide—they may or may not be direct causes.

Risk Factors

  • Family history of suicide
  • Family history of child maltreatment
  • Previous suicide attempt(s)
  • History of mental disorders, particularly clinical depression
  • History of alcohol and substance abuse
  • Feelings of hopelessness
  • Impulsive or aggressive tendencies
  • Cultural and religious beliefs (e.g., belief that suicide is noble resolution of a personal dilemma)
  • Local epidemics of suicide
  • Isolation, a feeling of being cut off from other people
  • Barriers to accessing mental health treatment
  • Loss (relational, social, work, or financial)
  • Physical illness
  • Easy access to lethal methods
  • Unwillingness to seek help because of the stigma attached to mental health and substance abuse disorders or to suicidal thoughts

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