Both these groups had many experiences in common, such as feeling it as a real experience, a bright light at the end of the tunnel, floating away from and looking at your own body, meeting departed family members, and an exciting and intense feeling of peace, loss of fear of death and feeling of being a part of something universal. This suggests that NDEs reflect changes in the brain on approaching death.
In many cultures, the use of psychoactive drugs was part of religious practice. NDEs are probably based in brain biology, although it is near impossible to detect what changes take place in the brain during an NDE, we can compare by linguistic analysis the NDE reports with these drug-induced hallucinations.
By researching many NDE stories, collected over many years and comparing them a with the large experience anecdotes found in the Erowid Experience Vaults, a collection of first-hand descriptions with drugs they found remarkable similarities. While many psychoactive drugs were tried the highest comparison were with the hallucinogen Ketamine. Other drugs, such as LSD and DMT showed similar experiences.
DMT is found in South American plants but is also made in the brain, leading to the speculation that endogenous DMT might explain NDEs. Future research will show if this conclusion is correct but the researchers suggest that NDEs have such a lasting effect, Ketamine could be used to induce an NDE like state in terminal ill patients. To relieve anxiety about death. The research is continuing so stay tuned.