It is very difficult to really know - My son had a psychotic episode after taking lsd last summer combined with no sleep for one week while out of town with "friends". We are still trying to determine what he really has. He has been seeking neurofeedback therapy and at this center, they believe he has HPPD. One of the therapists that works there had it many years ago and he in fact did have Voices and visual hallucinations as did my son. The psychologist agreed that the episode could have been brought on by the drugs and lack of sleep alone. We do not have any family history of Schizophrenia. I have been trying to really figure it all out and we we think he could have depressive psychosis since he had done well for a period of time without medications. However; taking a year off from school to heal his brain made him feel ashamed and he withdrew from people and fell into a deep depression and experience some hallucinations. We decided at that time to put him on an antipsychotic (be sure to take the Genesight test if you need to be put on an antidepressant or antipsychotic)! --- SAD That most psychiatrists have never even heard of this test which is AMAZING to help get you on the proper medication based on your genetics! Anyhow - we are now at the point of struggling with being on medication when we really do not know what the true diagnosis is. I actually logged on to this site to see if others have experienced this as well.