Psychobiology of Altered States of Consciousness

Abstract

The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurringspontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychologicalmeans, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches.The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which theycan be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiologicalapproach revealed that the different states of consciousness are mainly brought about by acompromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemicaland metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, andtechniques of self-control can also temporarily alter brain functioning and conscious experience.