I just listened to an old "This American Life" episode in which a woman was diagnosed as HIV positive, put on AZT and other meds. She developed AIDS related dementia. Three years into this she sought help from a maverick physician to help with her severe symptoms. As a part of his initial work-up he did a lot of tests, called her into the room and told her that she was not HIV positive. Most of her symptoms were from the meds.
Her initial diagnosis wasn't from a false positive but was from a religious counselor who lied about her results with the hope that she would repent from her "sins" of being gay and seek "treatment" to make her "not gay."
On the medication/longevity issue there is a study (paraphrasing from memory) that found that people taking neuroleptics lived on average 25 years less. This number seems high but I can't help but believe that that many medications shorten lives.
BTW, regarding dementia and meds. I took aricept very briefly for some wacky reason not related to cognition and it made me feel very dull. I understand that it's efficacy is pretty questionable and has horrendous side effects for some. Here are some reviews form "ask a patient."
http://www.askapatient.com/viewratin...0&name=ARICEPT