If the Shabbaton due to be led by Rabbi Zac Kamenetz this weekend were being held in the UK, it might have prompted a visit from the police. As well as praying, participants will be doing breathing exercises, meditation and singing in preparation for what happens after havdalah — when they will join a “sacred cannabis circle”.

The event takes place at Urban Adamah, the eco-Jewish farm in Berkeley, California, one of the 19 states where cannabis is legal for recreational use. It will mark a step towards Rabbi Kamenetz’s long-term ambition to become “the first psychedelic-assisted rabbinic therapist”.

He is part of an embryonic movement looking to explore the interface between Judaism and mind-altering substances, which came to attention last year with the two-day Jewish Psychedelic Summit in the USA. While some religious groups have long used entheogens — psychoactive substances — in ritual, Judaism is not usually associated with them.

But Rabbi Kamenetz believes that such substances, imbibed in the right environment, can provide a gateway to that deep form of inner experience we call mystical. “I do not advocate anyone taking an illegal substances that is not part of a controlled experiment,” he has stressed.

The Jewish psychedelic movement has emerged at a time when scientists are increasingly investigating the potential benefits of currently banned narcotics for treating depression and other mental illnesses. Rabbi Kamenetz believes that society will eventually come to recognise their positive effects more widely and looks forward to the day when he will be able to open a Jewish centre where people can use them to “explore their inner content, the divine within them”.

“We need to create religious significance for these substances,” he said in an interview with the IDRA Hour podcast. “They might treat PTSD (post-traumatic stress disorder), they might treat depression or bulimia, but we have to be able to understand them in the sense of our religious tradition.

“When can you take these things? Who should you be with? What is the preparation like? When you receive insight, how does it factor into the rest of our revealed tradition?”

Rabbi Zac Kamenetz

Rabbi Zac Kamenetz

After leaving his job as director of Jewish living and learning of the San Francisco Jewish Community Centre, he founded Shefa — a kabbalistic term that alludes to the divine “flow” of goodness into the universe. Its mission is to support “safe and skilful explorations of expanded states of consciousness rooted in sacred Jewish traditions”.

The power of a transcendent experience was something he first felt as a teenager, though it came without the assistance of any external substance. Raised in a Reform household, he had little time for synagogue after barmitzvah but when he was 15, his parents persuaded him to go on a trip to Israel.

An archaelogical guide was explaining the site of Tel Gezer in the Judean hills when “I felt the brilliant bright light opening up my mind in a way that I could not even describe to anyone,” he recalled. “It was maybe just a flash. But I was almost completely changed from that moment on. I felt as though I was being held by God’s hands. And the moment it was over, I knew it was time for me to become a religious person.”

Ten years ago, he received ordination as an Orthodox rabbi in Israel. But it was five years later that he came to see the possibility of psychedelics as a spiritual aid.

He took part in a research experiment where psilocybin — the active ingredient in magic mushrooms — was given by scientists to a group of clerics to see what effect it would have on them. His experience included the inner vision of the most familiar kabbalistic image, the Tree of Life, which symbolises the divine emanations that sustain Creation.

He co-founded the Jewish Psychedelic Summit with two women, Natalie Ginsberg, director of advocacy and policy of the Multi-Disciplinary Association for Psychedelic Studies and Madison Margolin, editorial director of the magazine and website, DoubleBlind.

Margolin told the podcast Judaism Unbound that Judaism itself was “psychedelic, a reflection and expression of altered states”. Shabbat enables “an altered state of consciousness” and the prohibitions of mundane activities like driving are meant to prevent disturbance of an elevated state of mind.

In a way, the summit can be seen the latest chapter of the counterculture that began in the 1960s. Experimenting with narcotics led some to explore spirituality, though it was often the traditions of East. But some found a path to Judaism — Margolin cited “cute Grateful Dead slogans like LSD, Let’s Start Davening”.

“People come from secular communities, do psychedelics and they start seeking spirituality,” she told Judaism Unbound. “And now because the evidence of Jewish mysticism is more available maybe than it was in the 60 and 70s, they might come to Judaism.”

There’s always been a current of mysticism in Judaism ever since the 70 elders ascended with Moses and Aaron and saw the sky-blue pavement beneath “the feet” of God. But the mystical tradition has largely been seen as the preserve of a religious elite.

Some actually claim a reference in the Torah to cannabis in the kaneh bosem, a fragrant ingredient of the oil used to anoint Aaron and the priests. (Etrogim apparently contain DMT, the active ingredient in ayahuasca, an hallucinogenic beverage derived from the “vine of souls” used by the Incas.)

If drugs could ever be used legally and safely as spiritual support, they would be a way of popularising mysticism.

But a London Beth Din-approved cannabis retreat is not likely any time soon.