LSD Gives Congenitally Blind Man Synesthesia-Like Hallucinations

A person with naturally occurring synesthesia experiences the sensory world in overlapping layers. Sounds are seen as colors and tastes are processed as sounds. Overall, there are 60 documented forms of synesthesia, many of which sounds like an LSD trip. Accordingly, scientists recently found that LSD can induce synesthesia-like experiences in people without the neurological condition.

In a case report published in the April edition of Consciousness and Cognition, University of Bath psychologists show that LSD-induced synesthesia does exist and that it manifests in a very unique way for those who are blind from birth. They argue in their report about a single congenitally blind man that synesthesia can be triggered by psychedelic drugs because “the plasticity of the nervous system allows the recognition and translation of auditory or tactile patterns into visual experiences.”

Their write-up only analyzes the experiences of one individual who had LSD-induced synesthesia nearly 40 years ago, but they’re confident this qualitative account stands as a novel finding. It’s also important to note that this individual sounds kind of awesome. The study authors write:

“In this paper, we provide a detailed insight into synesthetic hallucinations as a response to psychedelic drug use in a CB [congentially blind] ex-rock music singer (or ‘rock star’ by his own account) identified by the pseudonym Mr. Blue Pentagon (BP). BP’s personal experience provides us with a unique report on the psychological and sensorial alterations induced by hallucinogenic drugs, including an account on the absence of visual hallucinations, and a compelling look at the relationship between LSD induced synesthesia and cross-modal correspondences.”

Mr. Blue Pentagon was born two months premature in 1948 and an over-saturation of oxygen at his birth caused him to develop permanent, congenital blindness. He went on to be a successful, professional musician who enjoyed the regular vices of the 1970s — marijuana and psychedelics, especially a type of LSD called Blue Pentagon for its shape and color. He reported to the study authors that during his LSD experiences, he experienced music on a whole new, tactile level — it felt as if he was immersed in a “waterfall” and sounds “became three dimensional, deep and delayed.” Importantly, this synesthetic-like experience was limited to the senses of hearing and touch — his blindness wasn’t subdued in any way by the LSD.

“Every time I did acid, I experienced something new and spectacular,” he reported. “Obviously through the senses which are available to me! I never had any visual images come to me. I can’t see or imagine what light or dark might look like. With LSD and cannabis though, I experienced so much through my hearing, touch, and emotions that it was already enough for me to take!”

His experience reflects the findings of recent studies in which sighted people take LSD and their visual imagery increases because of increased connectivity between the brain’s parahippocampal cortex, which is integral to storing memories, and the visual cortex. Because he is blind, the psychologists hypothesize this effect of LSD had to manifest through touch and sound.

“In visual deprivation,” they write, “auditory to visual synesthesia is most common, implying that there might be an inordinate likelihood of cross-wiring between these senses in late blind populations.”

To explore this further, scientists will have to bring this sort of experience into the lab so they can quantify it beyond one self-report. Because synesthetic experiences have predominantly been linked to the visual areas of the brain, understanding how it manifests in the blind will be a fascinating step forward in our understanding of the senses. Psychoactive drugs have been used to study the senses since 1898 — but we’re still a ways from understanding the ripple effect entirely.