Suicidal behavior is a serious potential consequence of treatable mental disorders that include bipolar disorder, major depression, borderline personality disorder, substance use disorders, anxiety disorders, and post-traumatic stress disorder, among others. It is not a mental illness in itself but family, twin, and adoption studies support the view that the familial transmission of suicidal behavior is, in part, genetic.
A new study, which was published in The American Journal of Psychiatry, aimed to clarify the sources of parent-child transmission for suicide attempts and death by suicide. Findings of the Swedish population study show that the likelihood of suicide attempts can be transmitted across generations, probably via genetic effects. However, rearing could also play a role.
Do genes play a role in suicide attempts?
Lead author, Kenneth S. Kendler, M.D., who is also the director of the Virginia Institute for Psychiatric and Behavioral Genetics at Virginia Commonwealth University, told Medical Xpress that genes do play a significant role in a suicide attempt. Yet, this does not mean that it is the sole reason why it runs in families. The behavior can also be psychologically or culturally transmitted from their relatives. These findings highlight that genes are not the only factor that governs our actions. Suicidal behavior is complex and it originates from a mix of environmental experiences and genetic inheritance, the authors added.
As the eminent scholar and professor in the Department of Psychiatry, Kendler shares that their research is one of the most comprehensive studies that look at the parent-child transmission of suicide deaths and suicide attempts. Previous studies focused on the rates between siblings and twins.
For their research, the authors compared four types of families in Sweden: (1) intact nuclear families, characterized by the presence of a father and a mother, (2) families where the biological father did not live with the family, (3) families with a stepfather, and families with their adoptive and biological parents.
Parent-child transmission of suicide attempts based on the type of family
The researchers noted that there is a moderately lower association of suicide attempts where the stepfather helped in raising a child or the father did not live with the family home. However, the parent-child transmission of suicide attempt was almost equal parts nurture (rearing environment) and nature (genetics) across all family types.
Kendler said that if one is an adoptee, for instance, and they have an adoptive parent who raised them who attempted suicide and they have a biological parent who never attempted suicide, such conveys a virtually equal risk for the offspring to also attempt for a suicide. The risk would be twice as strong if the parent who’s reared that individual is also his biological parent, he added. They called such a source of parent-child resemblance as genes plus rearing.
The transmission of suicide attempts was also particularly strong to sons than to daughters in family types that were not adoptive. Furthermore, the nature of a parent transmitting the suicide attempt risk to a child is not the same as it is for suicide death.
Peter Buckley, M.D., interim CEO of VCU Health System, commented that the findings of the Swedish study underscore the important role that healthcare providers play in paying careful attention to the warning signs of suicide when they talk to their patients. For instance, healthcare providers can look at the family medical history of the patient. Buckley, who was not involved in the study, consider Dr. Kendler and team’s research “remarkable” as it helps advance the medical community’s knowledge of the impact of the home environment, family relationships, mental illness, addiction, and genetics on a person’s health.
Death by suicide
According to Our World in Data, 800,000 people around the world die from suicide every year. It is alarming as the number is twice those who died from homicide. Suicide is also found to be the leading cause of death, particularly in young people. Countries with the highest share of deaths from suicide in 2017 were Greenland (7.21%), South Korea (5.08%), Sri Lanka (3.59%), Qatar (3.88%), Kazakhstan (3.17%), Suriname (3.42%), and Guyana (3.41%). In the same period, the world suicide rate is found higher for men than for women. Firearms are one of the most common suicide methods. Another common method is deliberate poisoning from pesticides.
In an interactive chart, the scientific online publication shows that suicides globally follow a standard pattern of the older the age group, the higher the death rate. The suicide rate for people age 70 years old and above was 27.45 while it was 16.17 for age 50-69 and 11.6 for age 15-49.
Why are so many teens depressed?
Therese J. Borchard, author of the book Beyond Blue: Surviving Depression & Anxiety and Making the Most of Bad Genes, said via mental health treatment platform Discovery Mood that there is more stress today than in previous generations. It is such a feeling of physical and emotional tension that triggers mood disorders and depression. Those who are predisposed by their genes are “pretty much guaranteed some symptoms of depression” at difficult or confusing time of adolescence. The lack of family and community support, modern lifestyle, the unstructured technology, less exercise, more screen time, and less sunshine are factors that fall into the equation.
Discovery Mood shares the common indicators of depression among teens as follows: hopelessness or sadness, sluggishness or less active, low self-esteem, substance abuse, not caring about appearance, running away from home, decrease in desire to do things they used to like to do, physical ailments, problems in schools, and spending more time alone. Sadly, most parents would say that they can’t notice the difference between normal teen behavior or depression until after the fact. “What if I had recognized the signs?” one parent said.
Ping Qin, MD, Ph.D. of Psychiatric Times also previously mentioned the association between the molecular genetics of serotonin – a neurotransmitter in the human body – and suicidal behavior. The tryptophan hydroxylase involved in the synthesis of serotonin is linked with the concentration of serotonin metabolite (5-HIAA) in the cerebrospinal fluid. A low level of CSF 5-HIAA is associated with aggressive and suicidal behavior.
Understanding both genetic and environmental factors can help psychologists, psychiatrists, and all health-related professionals to identify people at high risk for the development of suicidal behavior to prevent suicide and help restore their confidence in life.