Altered States - Plot

Plot

Edward Jessup (William Hurt) is a university professor of abnormal psychology who, while studying schizophrenia, begins to think that "our other states of consciousness are as real as our waking states." Jessup begins experimenting with sensory-deprivation using a flotation tank, and he travels to Mexico to participate in what is apparently an Ayahuasca Ceremony, although his guide states that the Indigenous tribe they are meeting works with Amanita muscaria which they are collecting for next year's ceremonies. An indigenous elder was seen with Banisteriopsis caapi root in his hand prior to cutting Jessup's hand, adding the ingredient of blood. Immediately after consumption he experiences bizarre, intense imagery. The professor then returns to the U.S. with a tincture and begins taking it orally before each session in the flotation tank where he experiences a series of increasingly drastic psychological and physical transformations.

Edward's mind experiments cause him to experience actual, physical biological devolution. At one stage he emerges from the isolation tank as a feral and curiously small-statured, light-skinned Primitive Man. In a subsequent experiment he is regressed into a mostly amorphous mass of conscious, primordial matter. It is only the physical intervention of his wife Emily which brings him back from this latter, shocking transformation in which he seems poised on the brink of becoming a non-physical form of proto-consciousness and possibly disappearing from our version of reality altogether.

The experiments worsen, as Professor Jessup experiences episodes of involuntary spontaneous temporary partial devolution. This occurs outside of the isolation tank and without the intake of additional doses of the hallucinogenic tincture. His early reaction is more one of fascination than concern, but as his priorities gradually change due to Emily's determination to keep from losing him, he finally begins to act like someone who values his humanity.