THE biblical Israelites may have been high on a hallucinogenic plant when Moses brought the Ten Commandments down from Mount Sinai, according to a new study by an Israeli psychology professor. Writing in the British journal Time and Mind, Benny Shanon of Jerusalem's Hebrew University said two plants in the Sinai desert contain the same psychoactive molecules as those found in plants from which the powerful Amazonian hallucinogenic brew ayahuasca is prepared. The thunder, lightning and blaring of a trumpet which the Book of Exodus says emanated from Mount Sinai could just have been the imaginings of a people in an "altered state of awareness", Shanon hypothesised. "In advanced forms of ayahuasca inebriation, the seeing of light is accompanied by profound religious and spiritual feelings," Mr Shanon wrote. "On such occasions, one often feels that in seeing the light, one is encountering the ground of all Being ... many identify this power as God." Mr Shanon wrote that he was very familiar with the affects of the ayahuasca plant, having "partaken of the ... brew about 160 times in various locales and contexts". He said one of the psychoactive plants, harmal, found in the Sinai and elsewhere in the Middle East, has long been regarded by Jews in the region as having magical and curative powers.