Correlating HPA axis dysfunction with psychological factors such as ED could lead to a better understanding of the role of HPA abnormalities in adolescent suicide and may enhance preventive and treatment strategies.

In this exploratory case–control study, we investigated basal cortisol regulation in 5–16-year-old children, 3–6 months following PICU (paediatric intensive care) admission. This was nested within a study of child psychological and cognitive function; 47 children were assessed alongside 56 healthy controls. Saliva samples were collected three times per day (immediately after waking, waking +30 min, and waking +12 h) over two consecutive weekdays. In addition, data on posttraumatic stress symptoms were ascertained from 33 PICU admitted children using the Impact of Events Scale-8 (IES-8). Primary analysis revealed no significant differences in basal cortisol concentrations between PICU discharged children and healthy controls (p > 0.05). Secondary analysis in the PICU group identified a significant positive association between posttraumatic stress symptoms and evening (waking +12 h) cortisol concentrations (p = 0.004). However, when subject to multivariate analysis, evening cortisol was a modest independent predictor of IES-8 scores, relative to the presence of septic illness and poor pre-morbid health. We conclude that paediatric critical illness does not appear to result in marked perturbations to basal cortisol at 3–6 month following discharge. There was evidence of a link between evening cortisol and symptoms of PTSD, but this was not a robust effect and requires further elucidation.Electronic supplementary materialThe online version of this article (doi:10.1007/s00787-016-0933-3) contains supplementary material, which is available to authorized users.

Studies on the neurobiology of adolescent suicide should consider the biological specificities of this life stage and of gender differences during this period. Future research designs should also try to integrate findings in the psychological and biological domains. Prospective studies may help understand the process that leads from suicidal ideation to suicide attempts or completed suicides in this population.