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Methods:

Serum samples were collected from otherwise healthy, medication-free participants with chronic PTSD (n= 44; 50% female; M age= 30.34; SD= 8.11) and matched controls (n= 49; 53% female; M age= 30.53; SD= 6.57) during a night of sleep in a laboratory. Levels of TNF-α and IL-6 were measured at hours 0, 2, 4, 6, and 8 after typical sleep onset time using serial serum samples. Plasma cytokine levels were quantified using enzyme-linked immunosorbent assays.

Results:

Growth model analysis indicated a significant group by time interaction (t [247]=-2.92, p=. 005) for IL-6 and a significant group by gender by time interaction (t [275]= 2.02, p=. 04) for TNF-α. PTSD positive individuals seemed to have higher cytokine levels at sleep onset, but not at the end of their sleep cycle. Inverted U-shaped profiles of TNF-α for male controls indicated that their TNF-α levels peaked in the middle of the night (hour 4) and …