Sex differences in objective measures of sleep in post‐traumatic stress disorder and healthy control subjects

Abstract

Summary A growing literature shows prominent sex effects for risk for PTSD and associated medical comorbid burden. Prior research indicates that PTSD is associated with reduced slow wave sleep (SWS), which may have implications for overall health, and abnormalities in REM sleep, which have been implicated in specific PTSD symptoms, but most research has been conducted in male subjects. We therefore sought to compare objective measures of sleep in male and female PTSD subjects with age and sex-matched control subjects. We used a cross-sectional, 2×2 design (PTSD/control × female/male) involving 83 medically healthy, non-medicated adults aged 19–39 in the inpatient sleep laboratory. Visual analysis of EEG demonstrated that PTSD was associated with lower SWS duration (F(3,82)=7.63, p=.007) and SWS percent (F(3,82)=6.11, p=.016). There was also a group by sex interaction effect for REM duration (F(3,82)=4.08, p=.047) and REM percent (F(3,82)=4.30, p=.041), explained by greater REM sleep in PTSD females as compared to control females, a difference not seen in male subjects. Quantitative EEG analysis demonstrated that PTSD was associated with lower energy in the delta spectrum (F(3,82)=6.79, p=.011) in NREM sleep. SWS and delta findings were more pronounced in males. Removal of PTSD subjects with comorbid MDD, who had greater PTSD severity, strengthened delta effects but reduced REM effects to non-significance. These findings support prior evidence that PTSD is associated with impairment in the homeostatic function of sleep, especially in men with the disorder. These findings suggest that group by sex interaction effects on REM may occur with more severe PTSD or with PTSD comorbid with MDD.

Hyperinsulinemic response to oral glucose challenge in individuals with posttraumatic stress disorder

“…Inclusion criteria for both groups was 20–50 years of age and body mass index (BMI) <30 kg/m 2 (O’Donovan et al, 2011; Richards et al, 2013). Exclusion criteria included: history of traumatic brain injury; presence of neurologic disorders or systemic illness; sleep apnea; pregnancy; alcohol abuse in the previous 2 years, substance abuse in the previous 1 year; any history of psychiatric disorder with psychotic features, bipolar disorder or compulsive disorders; and use of any psychiatric, anticonvulsant, antihypertensive, steroidal, lipid-lowering, or any other prescription medications or estrogen replacement therapy.…”

“…The recording montage consisted of C3/A2, C4/A1, O1/A2 and O2/A1 electroencephalograms, bilateral electroculograms, a bipolar submental electromyogram, bilateral anterior tibialis electromyograms and electrocardiograms (Richards et al, 2013; Rechtschaffen and Kales, 1968). Electrode impedance was set at <5000 ohms.…”

“…PSA was conducted on all epochs of sleep. As previously described (Richards et al, 2013), Pass Plus was used to perform Fast-fourier transformation analysis on 4.0-s Welch tapered windows with 2-s overlap, yielding 15 windows per 30-s epoch. Power spectra for delta (1–4 Hz) was used in this current analysis to determine whether delta energy was a potential mediator of the relationship between PTSD status and glucose tolerance.…”

Effects of sleep on memory for conditioned fear and fear extinction.

“…However, gender differences in the relationship between PTSD and sleep have now begun to be reported (Kobayashi, Cowdin, & Mellman, 2012; Kobayashi & Mellman, 2012; Richards et al, 2013). For example, observed sex differences in the sleep symptoms of PTSD may vary with hormonal levels and phase of the menstrual cycle in women (Kobayashi et al, 2012).…”

EEG correlates of the severity of posttraumatic stress symptoms: A systematic review of the dimensional PTSD literature

“…Woodward et al (2000) found that the non-REM-sleep sigma-band spectral power exhibited a strong positive correlation with the hyperarousal symptoms cluster. The non-REM delta energy did not exhibit a significant correlation with the overall PTSS severity or symptoms clusters (Richards et al, 2013).…”