Inducing Death Thoughts Reduces the Cortisol Response to Psychosocial Stress Similar to the Effects of Early-life Adversity: A Life-history Perspective

Purpose Early-life adversity (ELA) affects health by altering the hypothalamic–pituitary–adrenal (HPA) axis. Most studies show that ELA blunts HPA responsivity while others show the opposite. To explain this inconsistency, researchers investigate factors that alter associations between ELA and HPA responsivity. One factor could be conditions that participants encounter before exposure to stressors. Life-history theory suggests ELA alters HPA function by signalling high mortality. Similarly, death thoughts signal acute mortality. Research suggests that thinking about death induces behaviors typical of ELA subjects. We therefore tested whether death thoughts before acute stress mimics the effects of ELA on HPA responsivity. Methods One hundred twenty eight healthy young men were classified as high or low ELA based on retrospective self-report, and then primed with death thoughts (experimental group) or completed neutral questionnaires (control group). They then underwent a psychosocial stress task. Salivary cortisol was sampled repeatedly to assess HPA responsivity to stress. Results In the control group, higher ELA correlated with lower cortisol responsivity. In the experimental group, subjects with high ELA did not show altered cortisol responsivity, but low ELA participants displayed significantly blunted responsivity in response to death thoughts. Thus, low ELA participants primed with death thoughts resembled high ELA participants not exposed to death thoughts. Conclusion Our findings suggest that subtle death cues present in the testing environment may confound associations between ELA and HPA function and should be controlled for in future studies. We discuss how life-history theory could explain how both long-term (ELA) and acute (mortality salience) experiences alter HPA function.