If you are interested in this sort of thing, I'd strongly recommend "The Secret Chief Revealed",[1] which goes in to detail on the playlist selection for psychedelic therapy and many other related topics. It's a truly excellent book on the subject.

[1] - https://www.amazon.com/Secret-Chief-Revealed-Myron-Stolaroff...

For a little balance to this sordid, lurid, and sensationalistic account of psychedelic therapy, I'd recommend reading "The Secret Chief Revealed"[1] and Cary Grant's own accounts of his LSD experiences.[2]

An excerpt from the latter:

  "I learned may things in the quiet of that small room. I learned to   accept the responsibility for my own actions, and to blame myself   and no one else for circumstances of my own creating. I learned that   no one else was keeping me unhappy but me" 

[1] - https://www.amazon.com/Secret-Chief-Revealed-Myron-Stolaroff...

[2] - https://spectregroup.wordpress.com/2008/02/10/cary-grants-th...

It is possible in more countries than you might expect.

I strongly recommend reading The Secret Chief Revealed,[1] for a taste of how this has been done even in countries where prohibition rages, like the US.

You would also profit from following the links. reading up on, and perhaps contacting the various people and organizations listed in the Wikipedia article on Psychedelic Therapy.[2]

[1] - http://www.amazon.com/Secret-Chief-Revealed-Myron-Stolaroff/...

[2] - https://en.wikipedia.org/wiki/Psychedelic_therapy

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]

[1] - http://www.matrixmasters.net/archive/Playalogues/131-Danfort...

[2] - https://www.erowid.org/culture/characters/grob_charles/grob_...

[3] - http://www.amazon.com/Secret-Chief-Revealed-Myron-Stolaroff/...

[4] - https://www.erowid.org/psychoactives/faqs/psychedelic_experi...

[5] - http://csp.org/nicholas/A59.html

[6] - https://www.erowid.org/psychoactives/guides/guides_article2....

[7] - http://www.maps.org/gateway/%5B55%5D181-197.html

[8] - http://www.maps.org/news-letters/v09n1/09124mar.html