In general, you’re going to have a hard time researching this precisely because hallucinogens are so illegal. For example, when I was researching http://en.wikipedia.org/wiki/LSD_and_schizophrenia the area was just gearing up to really deal with the various confounds and alternate explanations when LSD was outlawed and bam, now the only studies you can do are of illegal users who tend to have huge confounds like abusing all sorts of other drugs or taking extremely nasty psychiatric drugs or just being intrinsically less mentally healthy.
(Likewise, looking into modafinil and schizophrenia was complicated by the fact that no studies directly bore on the problem, which will likely be an issue for you as well once you exhausted the few studies which are looking for specific benefits.)
Your best bet is probably looking for the modern trials investigating substances like psilocybin for PTSD, fear of death, etc. I know at least a few exist.
In general, you’re going to have a hard time researching this precisely because hallucinogens are so illegal. For example, when I was researching http://en.wikipedia.org/wiki/LSD_and_schizophrenia the area was just gearing up to really deal with the various confounds and alternate explanations when LSD was outlawed and bam, now the only studies you can do are of illegal users who tend to have huge confounds like abusing all sorts of other drugs or taking extremely nasty psychiatric drugs or just being intrinsically less mentally healthy.
(Likewise, looking into modafinil and schizophrenia was complicated by the fact that no studies directly bore on the problem, which will likely be an issue for you as well once you exhausted the few studies which are looking for specific benefits.)
Your best bet is probably looking for the modern trials investigating substances like psilocybin for PTSD, fear of death, etc. I know at least a few exist.