There was a clinical study done in London in a carefully controlled environment for people suffering from depression, it helped some long term and many short term. In Israel it was used for terminally ill patients who had extreme death anxiety it was found to help all of those in the test. I have never used it myself due to lack of opportunity. Interestingly it seems that LSD, magic mushrooms, etc don't enhance brain activity, they reduce it to the extent that all filters are removed so that one sees 'reality' for what it is, just a manifestation of consciousness. The cognitive scientist Donald Hoffman has, after using mathematics in the evolutionary game theory and computer modelling, hypothesized that perceived reality isn't the truth, it is consciousness and agents of consciousness manifesting a 'reality' that ensures our survival, a survival of conscious agents, which only perceive that which is necessary, everything else is filtered out.