What is Schizophrenia
a long-term mental disorder of a type involving a breakdown in the relation between thought, emotion, and behavior, leading to faulty perception, inappropriate actions and feelings, withdrawal from reality and personal relationships into fantasy and delusion, and a sense of mental fragmentation.
Syd Barrett, a founding member of the band Pink Floyd and one of the most legendary rock stars to develop a mental illness - most likely schizophrenia (triggered, it is said, by significant drug use as well as the stress and pressure of his career),
How-you can inherit it drug use can trigger it and other diseases can also trigger it,
Why-you can develop it anytime in your life. Symptoms include Hallucinations,Delusions and many more.
One fact is that Syd Barrett left Pink Floyd due to this mental illness.