Elevated morning serum interleukin (IL)-6 or evening salivary cortisol concentrations predict posttraumatic stress disorder in children and adolescents six months after a motor vehicle accident

SummaryBackgroundThis study examined prospectively the activity of the hypothalamic–pituitary–adrenal axis, the sympathetic nervous system and inflammatory factors in children shortly after a motor vehicle accident (MVA) in relation to later posttraumatic stress disorder (PTSD) development.Patients and methodsFifty six children, aged 7–18, were studied after an MVA and 1 and 6 months later; 40 subjects served as controls. Morning serum cortisol and interleukin (IL)-6 and plasma catecholamine concentrations were measured within 24 h after the event. Salivary cortisol was measured 5 times at defined time points during the same day. PTSD diagnoses 1 and 6 months later were based on K-SADS interview.ResultsMorning serum IL-6 concentrations, measured within the first 24 h after the accident, were higher in children that developed PTSD 6 months later than those who did not and those of the control group. Longitudinal IL-6 measurements revealed normalization of IL-6 in the PTSD group, while no differences between the three groups were detected 1 and 6 months later. Evening salivary cortisol and morning serum IL-6 after the accident were positively inter-related (r=0.54, p<0.001) and in separate regression analyses both predicted PTSD development 6 months later. In contrast, morning serum IL-6 did nor correlate with morning serum or salivary cortisol concentrations.ConclusionsImmediate posttraumatic alterations in neuroendocrine or inflammatory factors—increased evening salivary cortisol and/or increased morning serum IL-6 concentrations—are involved in subsequent PTSD development in children and adolescents.