The phenomena of loss of insight, dulling of consciousness, and loss of inhibition occuring in patients with brain disease are described. These are not explicable solely in terms of a lesion in a particular portion of the brain or as the result of the disruption of a specific neurophysiological mechanism.These modes of behavior can be more fruitfully considered in terms of altered patterns of social interaction or language, appearing as modes of adaptation to the stress of illness and incapacity. The relationship of brain dysfunction to the premorbid personality and the cultural milieu is discussed.Abstract Teaser