I suppose I don't understand the point of taking psychedelics if they only lead to psychosis and HPPD.  That does't sound like a very likely way to win over the synical hearts of naysayers either,  telling them that psychedelics induce insanity, HPPD etc or that they keep you from functioning in the real world. 

While I do believe that negative side effects can occur because of psychedelic use.  I personally believe this is a result of people fighting with all their might to try and stay or remain "sane" or "normal" or what ever in the midst of a psychedelic tsunami.

IMO sanity is just a more comfortable version of complete illusion.