I am a medical student. I recently finished my psychiatry rotation. Of everything they taught me to remember about LSD, the most important thing for us to remember from a psychiatric standpoint was that, LSD can be THE factor that induces schizophrenia if you have a predisposition towards it. This fact is so important that it shows up on medical board examination year after year. As a 20 year old male with a family history of schizophrenia your exact case would be THE board question to ask as you appear to fit the criteria for a 1st episode of schizophrenia. You are male, 20 years old, have a family history, and are about to experience your first hit of LSD. Oddly enough, I was in the psychiatry clinical rotation with another student who stated the exact same thing had happened to a friend of his who was "never the same" after his first hit of LSD and he ended up killing himself.
On a side note, some psychiatrists believe that schizophrenics have a propensity gravitate towards marijuana as a "self-medication" technique.