title: Evening-type military veterans report worse lifetime posttraumatic stress symptoms and greater brainstem activity across wakefulness and REM sleep.
abstract: Evening chronotypes exhibit increased rates of affective dyregulation and sleep disturbances (e.g., insomnia and nightmares). Such symptoms are common to military veterans with posttraumatic stress disorder (PTSD); however, the influence of chronotype on this population remains unknown. We examined behavioral, psychological, and neural correlates of chronotype in 36 combat-exposed military veterans with varying degrees of posttraumatic stress symptomatology. We employed FDG-PET to assess neural activity across wakefulness and rapid eye movement (REM) sleep. We used polysomnography and diaries to monitor sleep, and a self-report survey to measure chronotype. Eveningness was associated with greater lifetime PTSD symptoms, more disturbed sleep, and more frequent and intense nightmares. Eveningness was also associated with greater brain activity in posterior cingulate/precuneus and brainstem regions across wakefulness and REM sleep, overlapping with regions related to arousal and REM sleep generation. Chronotype may be an important correlate of neural activity in REM sleep-generating and/or arousal regulatory regions among combat-exposed veterans with PTSD symptoms. Further investigations of the role of chronotype in PTSD are warranted.
authors.affiliation: Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
authors.forename: Brant P
authors.initials: BP
authors.lastname: Hasler
authors.forename: Salvatore P
authors.initials: SP
authors.lastname: Insana
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: James
authors.forename: Anne
authors.initials: A
authors.lastname: Germain
mesh_terms: D000328:Adult; D001933:Brain Stem / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D017286:Polysomnography; D049268:Positron-Emission Tomography; D012893:Sleep Wake Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D012895:Sleep, REM / Q000502:physiology*; D013313:Stress Disorders, Post-Traumatic / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology*; D014728:Veterans / Q000523:psychology; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: Chronotype; Imaging; Nightmares; PTSD; Sleep; Veterans