The drug was mentioned in 'Altered States'.

In the 1980 movie "Altered States" William Hurt mentions to his soon wife to be- played by Blair Brown- that the girl being treated in the clinic is being shot up with DMT. The doctors ask her if she is less anxious and she says "yes very much so", and when asked if she has any special feelings she says "my heart feels like it is being touched by Christ"
I watched this documentary and quite frankly i would be afraid to try it even under clinical supervision. It sounds like it makes LSD look like Tylenol.

"He's not the messiah,he's a very,very,naughty boy,now,piss off" Monty Pythons "Life of Brian"