Research has shown that there is a genetic risk factor for suicide [1]. However, until now, very few studies have looked at family history [2] of suicide to determine how it affects second- and third-degree relatives and the maternal, paternal, or spousal influences. Because suicide is predicted to take nearly 1.5 million lives by the year 2020, according to the World Health Organization, being able to identify and treat those most vulnerable for suicidal ideations is vitally important. Current research has suggested the family risk factor for suicide to be anywhere between 17% and 55%. To get a more defined estimate of how suicide runs in families and how environmental factors impact the risk for suicide, D. Tidamalm of the Department of Clinical Neuroscience at Karolinska Institutet in Stockholm analyzed more than 50 years of data from the entire Swedish population. Tidamalm and colleagues assessed how many of the Swedes who had committed suicide during those years, a total of 83,951, had a relative who had also died from suicide, and they compared those rates to a control group.
The research revealed that full siblings had a higher risk for suicide than maternal half-siblings. However, maternal half-siblings were more likely to die by suicide than paternal half-siblings, perhaps because of shared environments. The study showed that identical twins were more vulnerable than fraternal twins, and even cousins were 50% more likely to commit suicide than the control group. Environment influenced the risk for suicide significantly as well. Full siblings were three times more likely to die by suicide than the children of suicide victims, whose risk was twice as high as the controls. Even spouses were more likely to commit suicide than the control groups. Tidamalm believes that degree of relation, combined with environment, is an important element for exploration in treatment. Tidamalm added, “The results confirm the importance of considering the family history of suicide when assessing suicide risk in clinical practice or when designing and administering preventive interventions.”
Reference:
Tidamalm, D., Runeson, B., Waern, M., Frisell, T., Carlstrom, E., Lichtenstein, P., Langstrom, N. Familial Clustering of Suicide Risk: A Total Population Study of 11.4 Million Individuals. Psychological Medicine 41.12 (2011): 22527-534. Print.