title: Syndrome of acute anxiety among marines after recent arrival at high altitude.
abstract: Management of mental health is critical for maintenance of readiness in austere military environments. Emerging evidence implicates hypoxia as an environmental trigger of anxiety spectrum symptomatology. One thousand thirty-six unacclimatized infantry Marines ascended from sea level to the Marine Corps Mountain Warfare Training Center (2,061-3,383 m) for a 30-day exercise. Within the first 6 days of training, 7 servicemen presented with severe, acute anxiety/panic with typical accompanying signs of sympathetic activation and no classic symptoms of acute mountain sickness (including headache). Four had a history of well-controlled psychiatric diagnoses. Invariably, cardiopulmonary and neurological evaluations were unrevealing, and acute cardiopulmonary events were excluded within limits of expeditionary diagnostic capabilities. All patients responded clinically to oxygen, rest, and benzodiazepines, returning to baseline function the same day. The unexpected onset of 7 cases of acute anxiety symptomatology coincident with recent arrival at moderate-to-high altitudes represents a highly unusual incidence and temporal distribution, suggestive of hypobaric hypoxemia as the proximal cause. We propose acute hypoxic physiological anxiety (AHPA) as a unique member of the spectrum of altitude-associated neurological disorders. Recognition of AHPA is particularly relevant in a military population; warfighters with anxiety spectrum diagnoses may have a recognizable and possibly preventable vulnerability.
authors.affiliation: United States Marine Corps, 1st Battalion, 1st Marines (1/1), P.O. Box 555412, Camp Pendleton, CA 92055.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Sracic
authors.affiliation: OIC Mountain & Cold Weather Medicine, Marine Corps Mountain Warfare Training Center, HC-83, Bridgeport, CA 93517.
authors.forename: Darren
authors.initials: D
authors.lastname: Thomas
authors.affiliation: United States Marine Corps, 1st Battalion, 1st Marines (1/1), P.O. Box 555412, Camp Pendleton, CA 92055.
authors.forename: Allen
authors.initials: A
authors.lastname: Pate
authors.affiliation: Warfighter Performance Department, Naval Health Research Center, 140 Sylvester Road, San Diego, CA 92106.
authors.forename: Jacob
authors.initials: J
authors.lastname: Norris
authors.affiliation: Department of Psychiatry, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093.
authors.forename: Marc
authors.initials: M
authors.lastname: Norman
authors.affiliation: Department of Psychiatry, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093.
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Gertsch
mesh_terms: D000208:Acute Disease; D000328:Adult; D000531:Altitude; D001007:Anxiety / Q000453:epidemiology*; D001569:Benzodiazepines / Q000627:therapeutic use; D006801:Humans; D000860:Hypoxia / Q000523:psychology*; D008297:Male; D008889:Military Personnel / Q000523:psychology; D013577:Syndrome
chemical_list: D001569:Benzodiazepines