brother has hallucination

My brother just told me a few days ago that he sees things that are not quite normal. He didn't go into great detail, so I am a bit vague in my explanation. We were talking about drugs, and he said he had never done any psychedelic drugs because he sees things (similar to what these drugs probably do) without ever having taken anything. He said he started having these experiences when he was in eighth grade(age 14). He is now 19. He says he has learned to just ignore the hallucinations. He also said it is probably something like schizophrenia. He had no denial of this possibility. The funny thing is that you would never know he deals with this. He does not act strange or have delusions. He has many friends. He is incredibly smart and successful in school, and he is very focused when it comes to his interests. His hallucinations do not appear to get in the way of his life. This makes me think that maybe his hallucinations are mild. I want to ask him more about it, but do not want to pry and have not had a chance. Could there be any other possible diagnosis other than schizophrenia? I read the list of symptoms and very few seem to correspond to how he acts.

i think its a good idea not to push your brother into answering your questions too quickly or too soon
it maybe an idea to ask any of your relations if they know of any history of these types of symptoms in the family.
hallucinations play a prominent role in schizophrenia and in the mania stage of bipolar
its not easy to say without more infomation from you

note that a drug doesnt have to be hallucinogenic for the user to experience hallucinations,
barbiturates, heroin, and alcohol can all cause hallucinations.

just because he hallucinates doens't mean he is schizophrenic, that was my main concern but mine are very mild (i mostly hear voices whenever its quite and i've seen things before) and the doctor said that i dont have schizophrenia, but i have schizo tendencies (along with ocd), my pychologist said i have G.A.D. and depression and those are making me hallucinate or something..

anyways have him see a doctor about this, its definately not a good idea to just let it go by, but we can't give you a definate answer.

saying that, hallucinations occur with alot of conditions including sensory deprivation, emotional stress, and great fatigue.