Commentary

Children's exposure to significant stress, adverse conditions and trauma is a well-known predictor of psychopathology persisting into adulthood. This association has powerful treatment/intervention implications, and also stimulates important hypotheses about how early stressors and disorders are linked. Yet, major questions remain that need to be addressed in order to maximise the potential yield of the association.

McLaughlin and colleagues tackled several of these issues in their paper. First, they tested a mechanism previously proposed by Hammen and colleagues1 that exposure to significant stressors during childhood renders individuals more sensitive to the effects of stress (higher probability of depression following stress, or depression in response to less stress, among those with early adversity). Second, the authors used the largest US epidemiological sample of diverse respondents to date (the National Epidemiological Survey of Alcohol and Related Conditions) to test the question for both men and women, and in reference to several different forms of disorders compared to most studies' focus on depression. Their findings established that exposure to early adversity does promote sensitivity to recent acute stressors in both men and women, extending to onset of post-traumatic stress disorder, and anxiety disorders, as well as major depression. Sensitisation was most apparent for those with exposure to multiple childhood adversities – which often ‘cluster’ together.

Many questions remain to be tested (how early the exposure, how chronic and severe, what changes underlie processes of sensitisation). Nevertheless, this study is compelling in clinical applications; the effects of harsh environments on children are devastating and persist over lifetimes, affecting adults and likely their own children as well. Unfortunately, scientific evidence continues to surpass efforts to address the environmental and family-level interventions that are indicated. Clinical interventions need to teach, bolster and support individuals' efforts to deal with, if not sidestep, major stressors where possible. Clearly, many of the very common and costly disorders of anxiety and depression require multifaceted and early interventions to break the cycle of stress occurrence and emotional disorders.