Effects of childhood adversity and cortisol levels on suicidal ideation and behaviour: Results from a general population study

Childhood trauma is known to increase the risk of suicidal ideation and behaviours, and has also been linked to hypothalamic pituitary adrenal (HPA) axis dysregulation measured in cortisol levels. Recent evidence has shown that adverse childhood experiences are associated with lower cortisol reactivity to stress and diminished cortisol levels upon awakening in individuals vulnerable to suicide. The present study aimed to investigate whether less traumatic long term difficulties during childhood produced a similar effect on suicidal ideation/behaviour and cortisol levels in a general population sample. Participants (N = 1094; mean age 53 years, 53.7% female) from a large cohort study completed retrospective measures of long-term difficulties during childhood and adolescent years and a measure of history of suicidal thoughts, plans and actions together with a measure of current psychological distress. 24-hour urinary free cortisol samples were collected over two days. The results showed that experiencing childhood long-term difficulties were associated with 21% higher odds of reporting suicidal thoughts or plans in adulthood. Early childhood and adolescent difficulties were equally important predictors of suicide thoughts and plans. However, childhood difficulties were not found to be associated with adult urinary free cortisol, nor were adulthood suicidal thoughts, plans and behaviour associated with adult urinary free cortisol levels. Future research should explore the extent to which childhood difficulties and stressors are related to other indicators of HPA axis functioning. The current findings have implications for clinicians and for the development of future suicide prevention interventions.