Post‐awakening changes in salivary cortisol in veterans with and without PTSD

Cortisol shows a well‐documented circadian rhythm with peak levels observed shortly after awakening and steadily decreasing values thereafter. This is a relatively robust diurnal pattern that is displayed by most non‐ill individuals, but recently it has been shown that in the general population some 10–15 per cent of individuals have ‘flat’ circadian cycles of cortisol. We have analyzed post‐awakening variations in levels of salivary cortisol in veterans without post‐traumatic stress disorder (PTSD), veterans with diagnosed PTSD that were not hospitalized, and hospitalized veterans with PTSD. ‘Flat’ circadian cycles of salivary cortisol were observed in 6 per cent of veterans without PTSD, 29 per cent of non‐hospitalized veterans with PTSD, and 42 per cent of veterans hospitalized for PTSD.