Child abuse as a risk factor for suicide in life: a selective overview

Suicide is a major public health issues. Suicide involves approximately one million deaths per year internationally. Annual fatalities due to suicide far exceed lives lost due to wars, homicides, and most natural disasters, and daily death-counts exceed the number of lives lost in the attack to the World Trade Center in 2001 A strong relationship between childhood abuse and adult suicidal behaviour has been found in several studies. In suicidal behaviour (SB), little attention has been paid to the possible interplay of genes with environmental factors, such as life events and social support. Stressful childhood events could modify children’s brain development in order to confer a vulnerability to SB that will be expressed in adulthood. Such stressful situations have been linked to abnormalities of serotonin. Decades of research have documented abnormalities in the hypothalamic adrenal (HPA) axis, and the noradrenergic and serotonergic systems in suicidal behavior and major depression. These three systems are also responsive to stress and raise the question as to how genes and childhood experience mold stress responses in the brain and thereby affect the risk of suicide. Abnormal stress response has been documented in both the HPA axis and noradrenergic system in suicidal behavior in the context of depression. Thus, evidence is emerging that aberrant DNA methylation is involved in psychopathologies and suicide risk. Research indicates that the glucocorticoid receptor is epigenetically regulated in the human brain, and associated with altered glucocorticoid receptor gene expression. Hypermethylation of the glucocorticoid receptor gene is found among suicide victims with a history of abuse in childhood, but not among controls or suicide victims with a negative history of childhood abuse. This point to the role of the environment in influencing substances that regulate gene expression and suggests a never ending struggle against abuses in childhoo