There’s madness up in the mountains. The world of high-altitude mountaineering is filled with anecdotes of climbers suffering from sudden bouts of psychosis, seemingly out of the blue. It’s always been presumed to be a symptom of general altitude sickness, however new research suggests it might actually be a distinct and undescribed medical entity.
Extreme-altitude psychosis often comes in the form of visual hallucinations, hearing voices, or distortions of the body’s other senses. In a 1999 study, one world-class mountaineer recalls: "I heard someone speaking French. The voice seemed to emanate from within my own body, and I heard myself responding. It was in French too – amazing, if you consider that I don't speak French at all." Others reported "smelling" cooked food, seeing crowds of people and horses in the distance, or even feeling like their body had suddenly grown to the size of a house.
In the past, this has been explained as high-altitude cerebral oedema, an acute mountain sickness that involves disorientation, confusion, dizziness, and splitting headaches. Scientists from Eurac Research and the Medical University of Innsbruck have recently found that the diagnosis of high-altitude cerebral oedema doesn't quite fit the bill.
For their study, published this month in the journal Psychological Medicine, researchers collected reports of nearly 80 psychotic episodes during high-altitude climbs. Based on this review, they believe that the high-altitude psychosis could be a “new medical entity” they have called isolated high-altitude psychosis.
“In our study we found that there was a group of symptoms which are purely psychotic; that is to say, that although they are indeed linked to altitude, they cannot be ascribed to a high-altitude cerebral oedema, nor to other organic factors such as fluid loss, infections or organic diseases,” Hermann Brugger, a mountain emergency medicine expert, explained in a statement.
They were still unable to pinpoint the exact cause of the problem. although it looks like it’s caused by a combination of oxygen deficiency, the pressure of self-sufficiency, and the early stages of swellings in certain areas of the brain. It was also noted that it only occurs at heights exceeding 7,000 meters (22,965 feet) above sea level and symptoms disappear when people return to normal altitudes with no lasting damage to their mental health.
Question marks still surround this phenomenon, but the researchers hope that further investigations could help unravel this bizarre phenomenon and potentially even save lives.
“There are probably unknown numbers of unreported accidents and deaths caused by psychoses. So as to reduce the number of such accidents, it is of the greatest importance to disseminate cognitive coping strategies which the mountaineers can themselves, or with the help of their partners, apply directly whilst on the mountain," added study author Katharina Hüfner.