SLEEP DEPRIVATION

Abstract

Drowsy states are altered states of consciousness, characterized by primary changes in attention, thinking and interest. In light drowsiness focal attention occurs only with deliberate, painful effort. In moderate drowsiness attention is desultory and passive, while interest is most easily directed to vivid stimuli. Integration of meanings on various levels is not possible. In severe drowsiness there is little or no conscious direction of attention. External stimuli are reacted to apathetically, if at all, but highly charged subjective events like visual hallucinations may occur. Each level of drowsiness is accompanied by the characteristic range of secondary changes in memory, perception, orientation and affect expression. To understand the nature of the secondary changes in visual perception and orientation, it was necessary to introduce 3 additional hypotheses about changes in preconscious functioning during drowsiness: preconscious processes are partially deautomatized, the less automatic becoming conscious and requiring active effort to complete; the processes remaining preconscious eventually undergo similar changes but require a greater degree of drowsiness; the increasing drowsy state leads to the further coloring of the contents of consciousness by affect and wishes represented by primary process mechanisms. Later, primary process thoughts intrude directly into consciousness, for example, as hallucinations. These hypotheses facilitated the prediction of subjective changes of individuals during drowsiness from prior psychological tests, and increased understanding of the subjective events during drowsiness. It was neccessary to consider the development, use, maintenance and interrelations of each modality in order to apply the hypotheses. The complexity of these considerations led to further recognition of the need for a better understanding of the processes of memory, perception and orientation. However, application of the hypotheses to current theories of memory and perception and to conceptions about the modalities of orientation, aided understanding of the nature and the place of occurrence of these secondary changes within discrete levels of drowsiness. The release of the primary process during drowsiness and the frequent occurrence of visual hallucinations while auditory hallucinations were absent suggested consideration on the tie between primary process thinking and visual thinking, and comparison hallucinations in sleep deprivation and schizophrenia.