Answer: The correct answer is "Dissociative Fugue".
Explanation:
Dissociative Fugue is also known as Fugue state.
It is a psychiatric disorder that characterizes by amnesia for personal information.
An individual while on a fugue state may forget who he/she is, what's his/her name, what's their personality like and so on.
While on a dissociative state, individuals usually wander, try to seek for help to police, hospitals and aid centers because they are not able to comprehend what's going on, they are usually asymptomatic except for a mild confusion and anxiety.
In this particular case, John Doe was not able to remember anything about himself, not where he lived or worked or even his name. His symptoms are most consistent with Dissociative Fugue.