It is believed that throughout history, many philosophers, writers and artists have produced their work after the intake of drugs. Salvador Dali, Mark Rothko and Andy Warhol, prolific writers like Aldous Huxley, Hunter S. Thompson and Jack Kerouac, and countless visionary musicians were a part of the long list of 20th-century drug-friendly creatives.

Amongst them was Jean-Paul Sartre, a key figure in philosophy. He was a French philosopher, playwright, novelist, political activist, biographer and literary critic.

Although drug use is never explicitly mentioned in his work, Sartre reportedly used barbiturates and amphetamines in his youth, and one powerful mescaline trip triggered visual hallucinations for several years. His literary fame began in 1938 when he wrote his first novel, the sombre and anxiety-driven Nausea. He established himself as an insightful existentialist philosopher in 1943 when he wrote Being and Nothingness, his most important philosophical work.

While working on a book about the imagination, Sartre sought to have a hallucinatory experience. He got the chance in 1935 when an old friend, Dr. Daniel Lagache, invited him into an experiment at Sainte-Anne’s hospital in Paris, where he was injected with mescaline and observed under controlled conditions. “Sartre does not appear to have had a bad trip in the classic sense of suffering a major and prolonged panic attack,” Gary Cox writes in his Sartre biography. “But it was not a good trip and he did not enjoy it.”

“Talking with Sartre: Conversations and Debates,” a selection of interviews from the ’70s, it was published by Yale University Press. An excerpt from that is mentioned below. Sartre stated in the interview, "Yeah, after I took mescaline, I started seeing crabs around me all the time. They followed me in the streets, into class. I got used to them. I would wake up in the morning and say, “Good morning, my little ones, how did you sleep?” I would talk to them all the time. I would say, “O.K., guys, we’re going into class now, so we have to be still and quiet,” and they would be there, around my desk, absolutely still, until the bell rang."

_{Nausea by Jean Paul Sartre}

This went on for a year before Sartre went to see his friend Jacques Lacan for psychoanalysis. “We concluded,” he says, “that it was a fear of becoming alone.” While he had previously confessed a fear of sea creatures, especially crabs, that went back to his childhood, after the mescaline trip, crabs featured prominently in his work, as Peter Royle shows at Philosophy Now.

Through psychoanalysis, Lacan and Sartre concluded that the crabs were a manifestation of Sartre’s fear of loneliness and becoming alienated from the people around him. The high dose of mescaline triggered his adolescent anxiety and induced an unpleasant feeling of isolation. Also, according to Lacan, Sartre hallucinated seeing crabs because he had developed an intense fear of sea creatures during his childhood.

Although Sartre eventually recovered from the drug-induced neurosis, the crabs he had hallucinated affected his life in a profound way. The experience partially inspired his novel Nausea and crabs became a recurring motif throughout his writings. For example, in his play, The Condemned of Altona, one of the characters claims he is being visited by intelligent crabs from the early 30th century who criticizes the horrors committed by humanity in the 20th century.