Psychedelics are having something of a resurgence in medicine, with researchers finding them useful for treating addiction and lowering suicide risk. Ecstasy shows potential for treating post-traumatic stress disorder, and LSD has been used as a complement to psychotherapy in the terminally ill.
It might be more accurate, though, to say scientists are re-discovering the usefulness of psychedelics. Many of today's banned drugs were used by psychiatrists in the 1950's, who claimed success in treating alcoholism and other mental health issues. Legendary actor Cary Grant even took LSD 100 times under the supervision of his therapist.
A new study published in Neuroscience of Consciousness offers some ideas about exactly why psychedelics may be be useful for mental health. "Psychedelics reliably induce an altered state of consciousness known as 'ego dissolution,'" the authors, Philip Gerrans and Chris Letheby, of the University of Adelaide in Australia, explain. The terminology predates much of the neuroscientific understanding of how the brain works, but describes "a feeling in which the mind is put in touch more directly and intensely with the world, producing a profound sense of connection and boundlessness." The sense of self—of an "I" separate from the rest of the world—dissipates or dissolves entirely. That'll sound familiar to anyone who's done psychedelics.
The experience of "ego dissolution," they argue, can be profoundly enlightening for patients in part because it allows them to see things differently. In fact, it allows them to see themselves in a radically different way, by temporarily dissolving their "model of the self." In everyday experience, we walk around with a sense of ourselves as cohesive individuals, separate from the world. We think of our experiences as happening to a stable entity, what we call our "self."