In 1968, when I was studying marijuana in Boston, I deliberately consumed an overdose (6 grams) of potent hashish in order to experience the reaction.
I took it orally, under observation, and kept notes as long as I was able.
The effects of the drug were felt within forty minutes and were pleasant but strong for about a half-hour. Thereafter, things became quite confusing.
I could not understand what was said to me, felt physically sick, and soon was unfit to do anything but lie in bed and wait for morning. Auditory hallucinations were prominent, especially threatening voices that rose in volume to a crescendo, the faded out.
For about twelve hours I remained in a stage of consciousness between sleeping and waking, marked by vivid nightmares.
Lucid intervals were rare; for much of the time I did not know where I was, even thinking I was six years old and sick from measles.
By morning, most of the worst symptoms had disappeared, but I had a powerful hangover that left me prostrate for another twenty-four hours.
I would not willingly repeat the experience.