Answer to Question 1
This recently identified disorder is associated with the AIDS epidemic. The symptoms include forgetfulness, concentration difficulties, mental slowness, mild motor difficulties, and apathetic, withdrawn behavior. These symptoms sometimes appear in an HIV-positive individual before the diagnosis of AIDS has been made. This type of dementia affects a disproportionate number of young adults, in contrast to the other dementias which usually have an onset after middle age. Finally, symptoms of AIDS dementia complex are sometimes difficult to distinguish from psychological and emotional reactions to the diagnosis of AIDS.
Answer to Question 2
Huntington's disease is transmitted by a single dominant gene; a person who has inherited the gene will inevitably develop the disorder. Among people who volunteer to be tested for the gene, those who learn they will develop the disorder are quite distressed at first. However, six months later their psychological state was generally better than it had been prior to testing. People for whom the test indicated freedom from the disorder were elated at first but then seemed to go into a slump. Sometimes this was because they had already made irreversible decisions based on their possible genetic status, such as being sterilized. Other people were negatively affected because they had unrealistically high expectations about how the test results would change their lives. There were similar numbers of negative reactions in the groups that got good news and bad news. People who had experienced psychological problems prior to the test had the worst outcome regardless of the test outcome.