Hello trish,   This question is what we'd call in the library world a "stumper."   I'm honestly not sure the answer so I would ask you to contact a medical doctor as I can't give medical advice.   I have never heard of schizophrenia being caused by a lack of oxygen; that isn't to say it's not possible, it could be possible, I just don't know.   You mentioned "black lung" so I doubt the following study refers to the person you care for; however, it talks about the topic.   Read the following news report about a study about newborns deprived oxgen, note it is only a study and possibly wasn't replicated elsewhere:   http://www.schizophrenia.com/newsletter/allnews/O2shortage.html   Regards, Chris