If you are interested in this question, I recommend listening to the following recording of a talk given by Alicia Danforth, research assistant to Dr. Charles Grob (who ran the psilocybin research study mentioned in this article).[1] She goes in to quite a lot of detail as to exactly how they conducted their study, and what measures they took to help prevent bad trips.
As supplementary reading, see the Erowid page on Dr. Charles Grob,[2] a book called The Secret Chief Revealed by Myron J. Stolaroff (about a famous psychedelic therapist),[3] and The Psychedelic Experience FAQ.[4] The book and FAQ have lots of great suggestions for having positive, constructive trips.
One of the key things you can do to increase the odds of having a good trip is having a trusted, experienced guide or sitter. To that end, I recommend the following sitter guidelines: [5][6][7][8]
A lot of bad trips are caused by anxiety. This anxiety can come from: societies view on drugs, the person thinking they are going to die, the legality of what they are doing, lack of a knowledgable trip-sitter, to name a few. I think taking a psychedelic in a setting as described in the article will help remove a lot of those common triggers to a bad trip.
I imagine that being able to carefully control the purity, dosage and the environment will go a long way. It is unfortunate that it is impossible to get illegal drugs of known purity, concentration, and quality.
If you can get approval to possess a Schedule I substance from the DEA, you can purchase drugs such as LSD and psilocybin from companies that manufacture them. They also come with certificates of analysis describing their purity.
I've just read a very interesting book after seeing it mentioned in HN's earlier discussion of LSD. It's by Dr. Rick Strassman, who conducted the first trials of a psychodelic held in the US in 20 years (using a potent psychodelic called DMD). Even after his trial was approved by the FDA and DEA, he struggled to find a supplier for human-quality DMT, although he had already procured a sufficient quantity of laboratory-quality of DMT for testing purposes.
It's a very interesting book -- I highly recommend it [0]. He's not a strong writer in terms of narrative (I found the book's pacing to be jarring given the intensity of experiences described), but he's very precise and describes some very interesting work, and some amazing experiences had by his subjects [0].
Most of this stuff is easy enough to produce in a controlled, safe manner. There are suppliers for medical-grade cocaine, for example, as it's used in a small set of procedures.
They don't say "this is to avoid a bad trip" but the article clearly explains how. EDIT: Actually, they do say "to avoid bad trips." I missed it the first time but noticed the description of the environments. Yup, it pays to actually read the article.
