What you read about mental illness is most likely fact. What psychiatrists put into books are objective and not meant to be personal. (Organic or substance-induced) psychosis and psychosis disorders (schizophrenia, bipolar, etc.) can produce very odd or abnormal thoughts and can effect the parts of the brain that regulate thinking, speech, organization, concentration, rationalization just to name a few.

And it's easy to misdiagnose someone suffering from a severe mental illness a lot of the time. The best you can do is to tell doctors what you are feeling and thinking in order for them to make an accurate diagnosis and provide you with proper treatment.