Psychosomatic Medicine 2:53-67 (1940)
© 1940 American Psychosomatic Society

Disorders of Mental Functioning Produced by Varying the Oxygen Tension of the Atmosphere

I. Effects of Low Oxygen Atmospheres on Normal Individuals and Patients with Psychoneurotic Disease

¹ Psychiatric Service, Bellevue Hospital and the Department of Medicine, College of Physicians and Surgeons, Columbia University, and the Presbyterian Hospital, New York City

The reactions of two groups of subjects, one consisting of 17 medical students, the other of 9 patients from the mental hygiene clinic of Bellevue Hospital, were studied prior to, during, and after exposure to 13 per cent oxygen for three hours. The basis for reaction evaluation was the "retention and recall" test, and in the student group, the Rorschach test as well. In addition, alterations in behavior, mood, speech and subjective complaints were recorded.

In executing the experimental procedure, the oxygen content of the atmophere was gradually lowered in one instance while in the other the concentration was lowered abruptly to a 13 per cent oxygen concentration. In the former experiment a more prolonged period of elation and a diminished frequency of somatic complaints were observed. Aside from the aforementioned differences, no other alterations were found to exist as a result of the difference in the technique of applying the reduced oxygen concentration.

In the student group, during the 3 hour inhalation of 13 per cent oxygen, all 17 complained of a frontal headache; mild dizziness, yawning, sense of oppression, pain in the joints and epigastrium, and tingling sensation in the fingers and toes were frequent. Changed perception of color and of their own body and vague, undefined fears were observed. Inability to concentrate occurred in all cases. This was especially pronounced by the end of the second hour. The perception of time was slower in that the time intervals were evaluated as shorter than actual. Mispronunciations were noted several times. Fifty-nine per cent showed shorter or longer periods of elation resembling the hypomanic mood, followed by dullness, drowsiness, and deep sleep. The ability to distinguish between sleep and reality showed some impairment. Forty per cent of the group did not show any period of elation. Irritability and dullness, resulting in listlessness and especially poor performances on the psychological tests, were noted. After the three hour residence in 13 per cent oxygen, lethargy, complaints of blankness, apathy, extreme fatigue, sense of estrangement and detachment from the world were observed in a great majority of the subjects.

In the patient group, somatic complaints were essentially the same as in the student group except that they were less pronounced and less frequent. A great majority of patients expressed the suspicion that some stimulating drug was added to the gas mixture, and they expressed a fear of death by suffocation during residence in the hood. Fifty-three per cent of the patients exhibited a prolonged period of excitement, extreme productivity, lack of inhibitions, frank sexual advances, sensations of well being, exaggerated self esteem, overactivity, restlessness and threatening behavior. The remaining forty-seven per cent of the patients did not show any period of excitement. They were irritable, dull and drowsy from the end of the first hour, and remained so throughout the experiment.

The students made 45.4 per cent more errors in the "retention and recall" test after inhalation of 13 per cent oxygen as compared with their normal test. Errors in the test occurred in 15 of the 17 students. The number of added words accounted for the poor performance. The added words expressed hesitation, perseveration, uncertainty, confabulation, and elaboration--a state closely related to organic confusion.

The patient group showed 19.2 per cent less errors as compared with their normal test. The number of added words, reflecting their usual preoccupations, was the chief reason for this high percentage of errors in the normal test. In 5 of 9 patients, the efficiency of response was better after inhalation of 13 per cent oxygen. Some degree of emotional relaxation was observed after the exposure to lowered oxygen.

Comparing the performances of both groups we find that the patients made 108 per cent more errors in the normal test as compared to the normal test of the students. Furthermore, the best performance of the patients, i.e., after the exposure to low oxygen, still showed 68 per cent more errors than the best performance of medical students in their normal test. The results with the Rorschach test (13) after the exposure to low oxygen as compared with the test done 4 to 8 weeks later showed only a superficial change. The differences observed indicated a swing in mood. Eleven of seventeen students manifested a hypomanic state without any actual dilatation of personality, that is merely a state of elation. The remaining six students exhibited a tendency toward depression. Reduced ability to form new and original associations was noted. The Rorschach test has substantiated the results obtained by objective observation and by the "retention and recall" test in that every individual follows his inherent pattern. Anoxia merely exposes and aggravates the pre-existing tendency.⁵

Note:

This study was carried out with the aid of a grant from the Linde Air Products Company and the Mary W. Rumsey Fund.