http://my.webmd.com/content/article/89/100279.htm?z=1728_00000_1000_nb_04June 25, 2004 -- Recalling a traumatic memory may provoke severe distress in people, even if the memory may be a product of their own imagination, according to a new study.
The study showed that people who claim to have been abducted by aliens show the same signs of distress, such as increased heart rate, sweating, and muscle tension, shown by people recalling more plausible traumatic events, such as wartime experiences.
Researchers say these signs of distress are often viewed as a testament to authenticity of a person's memory of a traumatic event, such as childhood abuse. But the researchers say these results show that physiological responses should not be used to verify traumatic memories in the evaluation of posttraumatic stress disorder (PTSD).
...Researchers say that for people who believe they have been abducted by aliens, recalling their abduction can provoke physiological reactions similar to those evoked by more verifiable stressful memories.
Therefore, they say physiological responses are not a valid indicator of whether a memory is real or not. [continued]
I assume this may just be a case of bad reporting but the article appears to say that it can't be so its not. As reported, the logic appears to be completely circular.