High-Altitude Psychosis Seen as Distinct from Altitude Sickness

In a new study of psychotic episodes at extreme altitudes, researchers have determined that high-altitude psychosis is a stand-alone medical illness, rather than a condition stemming from acute altitude sickness as had been previously believed.

High-altitude psychosis is a fairly well-known illness and is frequently mentioned in mountain literature. For example, a mountaineer may suddenly think he is being chased, start talking nonsense or change his route without any real reason.

For the study, emergency medicine doctors from Eurac Research in Italy and the Medical University of Innsbruck in Austria collected around 80 psychotic episodes from German mountain literature and systematically analyzed the symptoms described in them.

After much scientific scrutiny, the researchers concluded the condition is  a new medical entity: isolated high-altitude psychosis.

Until now, doctors had attributed these acoustic, optical, and olfactory hallucinations to organic causes. This may be because they frequently occur with symptoms such as severe headaches, dizziness, and impaired balance — side effects of a high-altitude cerebral edema, or swelling due to injury or inflammation.

“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 edema, nor to other organic factors such as fluid loss, infections or organic diseases,” said researcher Hermann Brugger, head of the Institute of Mountain Emergency Medicine at Eurac Research.

Isolated high-altitude psychosis is most likely to occur at heights exceeding 7,000 meters (22,965 feet) above sea level. So far, researchers have only been able to speculate on the causes. For example, it is possible that factors such as oxygen deficiency, the situation of being totally dependent on oneself and the early stages of swellings in certain areas of the brain could all be triggers for psychosis.

Importantly, the symptoms completely disappear once the mountaineer leaves the danger zone and comes down from the mountain. Furthermore, there does not appear to be any consequential damage.

“This discovery has allowed us to make a more thorough investigation of temporary psychoses in otherwise completely healthy people, an investigation which might yield important indications for the understanding of psychiatric diseases such as schizophrenia,” said researcher Dr. Katharina Hüfner, lecturer at the University Clinic in Innsbruck.

The new findings are also relevant because the syndrome increases the risk of accidents.

“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 themselves, or with the help of their partners, can apply directly while on the mountain,” said Hüfner.

Next, the researchers plan to collaborate with Nepalese doctors by undertaking further investigations in the Himalayas. They hope to find out, among other things, how frequently this illness occurs.

“The highest mountains in the world are maddeningly beautiful,” said Brugger. “It’s just that we had no idea that they could actually drive us to madness as well.”

The study findings are published in the journal Psychological Medicine.

Source: Eurac Research

Posted by Patricia Adams