New-onset anxiety disorders at high altitude.

Objective: Studies on the neurologic effects of high-altitude travel have focused on psychometric and cognitive testing and the long-term effects of hypoxia on memory and cognition. Few authors have discussed overt clinical psychiatric illness during high-altitude travel, and those few have focused on patients with preexisting psychiatric diagnoses. We describe a series of patients with new-onset anxiety disorders at high altitude treated at the Himalayan Rescue Association (HRA) clinic in Pheriche, Nepal (4240 m) in the spring season of 2006.

Methods: We report on all 6 cases of anxiety-related illness diagnosed at the HRA Pheriche Clinic during the spring season, 2006. Three cases, representing the 3 discrete types of illness we encountered, are described in detail.

Results: Six of 76 foreign patients and none of the 224 Nepalis seen during the season had anxiety-related primary diagnoses. None of the 6 patients had a history of psychiatric disorders or anxiety-related problems at low altitude. Three of the 6 patients were seen after hours, and all 6 required multiple visits. We describe 3 types of anxiety-related disorders: limited-symptom panic attacks induced by nocturnal periodic breathing, excessive health-related anxiety, and excessive emotionality.

Conclusions: Anxiety-related illness requires significant use of medical resources by high-altitude travelers. Further research is needed to define the epidemiology of anxiety-related disorders at high altitude, to quantify the contributions of various etiologic factors, and to identify safe, effective treatments.