Thursday, December 28, 2017

Isolated psychosis during exposure to very high and extreme altitude

Hüfner K, Brugger H, Kuster E, Dünsser F, Stawinoga AE, Turner R, Tomazin I, Sperner-Unterweger B. Isolated psychosis during exposure to very high and extreme altitude - characterisation of a new medical entity. Psychol Med. 2017 Dec 5:1-8. doi: 10.1017/S0033291717003397. [Epub ahead of print]

Psychotic episodes during exposure to very high or extreme altitude have been frequently reported in mountain literature, but not systematically analysed and acknowledged as a distinct clinical entity.

Episodes reported above 3500 m altitude with possible psychosis were collected from the lay literature and provide the basis for this observational study. Dimensional criteria of the Diagnostic and Statistical Manual of Mental Disorders were used for psychosis, and the Lake Louise Scoring criteria for acute mountain sickness and high-altitude cerebral oedema (HACE). Eighty-three of the episodes collected underwent a cluster analysis to identify similar groups. Ratings were done by two independent, trained researchers (κ values 0.6-1). Findings Cluster 1 included 51% (42/83) episodes without psychosis; cluster 2 22% (18/83) cases with psychosis, plus symptoms of HACE or mental status change from other origins; and cluster 3 28% (23/83) episodes with isolated psychosis. Possible risk factors of psychosis and associated somatic symptoms were analysed between the three clusters and revealed differences regarding the factors 'starvation' (χ2 test, p = 0.002), 'frostbite' (p = 0.024) and 'supplemental oxygen' (p = 0.046). Episodes with psychosis were reversible but associated with near accidents and accidents (p = 0.007, odds ratio 4.44).

Episodes of psychosis during exposure to high altitude are frequently reported, but have not been specifically examined or assigned to medical diagnoses. In addition to the risk of suffering from somatic mountain illnesses, climbers and workers at high altitude should be aware of the potential occurrence of psychotic episodes, the associated risks and respective coping strategies.

From the article

‘I first met Jimmy on the Balcony, a cold windswept snow shelf high up on the southeast ridge of Mount Everest. At an altitude of more than 8200 meters our introduction had been brief, with little more than a muffled “hello” and a few words of encouragement passing between us. Over my right shoulder, obscured by the bulky oxygen mask and the rim of down that smothered my face, I was sure I could see Jimmy moving lightly in the darkness. But despite him remaining close by me for the rest of the day, I didn't see him again’…

We analysed the distribution of accidents and near accidents across the clusters: 12% (5/42) of cases were associated with accidents or near accidents in the PSYNO cluster, 59% (10/17, one missing) in PSYPLUS and 22% (5/23) in PSYISO (χ2 test, p = 0.001, z-test < 0.05 for PSYNO a, PSYPLUS b, PSYISO a). Overall, episodes without psychosis (cluster 1) were compared with episodes with psychosis (clusters 2 + 3). The latter were associated with a higher number of near accidents and accidents [cluster 1 12% (5/42), clusters 2 + 3 38% (15/40, one missing), χ2 test, p = 0.007, OR 4.44]. Episodes where individuals were considered to display symptomology congruent with AMS were not associated with a higher number of accidents or near accidents compared with episodes without AMS [acute mountain sickness] [28% (11/40) v. 21% (9/42, one missing), χ2 test, p = 0.522, OR 1.28]. While episodes where individuals were considered to display symptomology congruent with HACE showed higher number of accidents and near accidents compared with episodes without HACE [42% (8/19) v. 19% (12/63, one missing), χ2 test, p = 0.04, OR 3.09]…

In conclusion, psychosis can occur at very high and extreme altitude, and reportedly in the absence of other signs and symptoms of HACE [high altitude cerebral edema]. Isolated HA psychosis should thus be considered a distinct and separate HA-related syndrome. It is important to inform subjects who intend to go to HA about the possibility of psychosis, in addition to the well-recognised somatic HA disorders. This should be part of the information campaign for HA travellers. Cognitive strategies (e.g. reality testing, Smailes et al. 2015) should be considered and practiced beforehand. This information has the potential to increase safety at HA, especially when with a partner or in a group. These findings are not only important for climbers and mountaineers but also for occupational HA work. To better describe HA psychosis, to determine its incidence, risk and trigger factors, treatment and patient's outcome, a prospective observational study should be performed. Additionally, in vitro studies could further ameliorate knowledge of the underlying pathophysiology. Since isolated psychosis at altitude shows some clinical features similar to schizophrenia, it could potentially serve as a reversible model of the disease; thus aiding in the investigation of pathophysiological concepts or new treatments for schizophrenia and related disorders.

Brugger P, Regard M, Landis T, Oelz O. Hallucinatory experiences in extreme-altitude climbers. Neuropsychiatry Neuropsychol Behav Neurol. 1999 Jan;12(1):67-71.

This study attempted a systematic investigation of incidence, type, and circumstances of anomalous perceptual experiences in a highly specialized group of healthy subjects, extreme-altitude climbers.

There is anecdotal evidence for a high incidence of anomalous perceptual experiences during mountain climbing at high altitudes.

In a structured interview, we asked eight world-class climbers, each of whom has reached altitudes above 8500 m without supplementary oxygen, about hallucinatory experiences during mountain climbing at various altitudes. A comprehensive neuropsychological, electroencephalographic, and magnetic resonance imaging evaluation was performed within a week of the interview (8).

All but one subject reported somesthetic illusions (distortions of body scheme) as well as visual and auditory pseudohallucinations (in this order of frequency of occurrence). A disproportionately large number of experiences above 6000 m as compared to below 6000 m were reported (relative to the total time spent at these different altitudes). Solo climbing and (in the case of somesthetic illusions) life-threatening danger were identified as probable triggers for anomalous perceptual experiences. No relationship between the number of reported experiences and neuropsychological impairment was found. Abnormalities in electroencephalographic (3 climbers) and magnetic resonance imaging (2 climbers) findings were likewise unrelated to the frequency of reported hallucinatory experiences.

The results confirm earlier anecdotal evidence for a considerable incidence of hallucinatory experiences during climbing at high altitudes. Apart from hypoxia, social deprivation and acute stress seem to play a role in the genesis of these experiences.

From the article 

"During the last few minutes [before the ascent had to be given up], I had the feeling that another person was climbing with me. He [although I 'knew' he was a man, I had no idea who he could have been] was always approximately 5 m behind me, and although I clearly saw that nobody was there, I continued to look over my shoulder again and again. The stronger I felt his being there, the stronger I noticed an 'empty feeling,' a distinct 'hollowness' of my body" (subject 5, climbing behind two companions at an altitude of 8300 m; exhausted but not in danger)....

"Despite the fog, I clearly saw these people. [...] I could make out individual faces and decided that I had never seen them before in my life" (subject 2, during a solo climb at an altitude between 5000 and 6000 m)....

"First I saw two horses, later on, just one horse but this time with a rider on its back. In this person, I recognized a remote acquaintance" (subject 1, describing an experience at an altitude of 4500 m).
"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 do not speak French at all..." (subject 1, solo climb below 6000 m)...

"For a few minutes, I heard some friends talk about technical problems or issues relating to our present situation. The voices were quite normal in loudness and intelligibility. I did not try to take part in the conversation" (subject 3, while resting at an altitude of approximately 7500 m).

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