As usual Christina's answer is very helpful.  I thought I'd enclose a link to a particularly helpful site where the answer to your question is discussed in even more detail. As a caveat, I'm a Behavioral Scientist with a son who has been terribly ill for several years with one of the many forms of Schizophrenia.  My son has absolutely no awareness of his illness and in fact uses much of the professional jargon that he learned while growing up at home to convince/confuse doctors and judges that he is entirely healthy despite behavioral manifestations to the contrary.  His ability to do that supposedly 'protects' him under HIPPA to remain in a state of continuous illness and his family in a continuous state of despair.   http://www.treatmentadvocacycenter.org/generalresources/article55.htm