Psychophysiological studies of eating disorders by means of visual evoked responses.

The psychic conditions of 14 patients with eating disorders were examined psychophysiologically. Visual evoked potentials (VEPs) and vertex potentials (V-potentials) as visual evoked responses (VERs) were recorded simultaneously at rest and during hyperventilation. The correlation between manifest anxiety measured by the MAS test and the increased amplitudes of VERs during hyperventilation was examined. The results showed that the psychic conditions of the typical anorexia nervosa patients were similar to a state of alexithymia, as they showed less manifest anxiety. The amplitudes of the VEPs and V-potentials did not increase during hyperventilation as did those of hysteric and obsessive-compulsive neurotic patients. Psychic conditions of patients suffering from the other type of eating disorders were contrary to the former group, viz., they showed much manifest anxiety. The amplitudes of the VERs increased markedly during hyperventilation as did those of anxiety neurotic patients. Mechanisms of increased amplitudes during hyperventilation as well as the correlation between manifest anxiety and anorexia nervosa are discussed. In conclusion, we would suggest that the typical cases of anorexia nervosa can be classified as psychosomatic disease and the atypical cases and the other eating disorders as neuroses.