A person is missing away from home and wandering with loss of recent memory with depersonalization, The diagnosis is

Dissociative Fugue: Dissociative fugue is characterised by episodes of wandering away (usually away from home). During the episode, the person usually adopts a new identity with complete amnesia for the earlier life. The onset is usually sudden, often in the presence of severe stress. The termination too is abrupt and is followed by amnesia for the episode, but with the recovery of memories of earlier life. The characteristic feature is the assumption of a purposeful new identity, with the absence of awareness of amnesia. A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 101