However, the
diagnostic validity of this kind of self-protection sign has not been
evaluated convincingly. Furthermore, unethical provocative maneuvers,
such as dropping alcohol in the nostrils or olfactory stimulation
using ammonium, should not be used to induce responsiveness in
patients deemed to be in feigned coma."

Quotes from http://www.memorylossonline.com/glossary/psychogenicamnesia.html
:

#randsent

"Psychogenic amnesia (also called functional amnesia) is a form of
amnesia which occurs in otherwise healthy people -- i.e., it is not
the result of a brain injury. It involves loss of important personal
information. Another term for this condition is functional amnesia."

#randsent

"In one form of psychogenic amnesia, called fugue state, individuals
may forget not only their pasts but their very identities. Despite the
many Hollywood movies depicting this phenomenon, fugue state is
extremely rare in real life. Fugue state normally resolves with time,
particularly with the help of therapy."