A 23-year-old man is brought into the emergency department after he was found wandering around a train station. He is alert and oriented to the emergency room, but cannot give his name. His wallet contains a driver’s license with his photo, but he denies recognition of the name on the license. He cannot explain why he was at the train station and cannot provide any details on his living situation, job, or family. The emergency contact in his phone leads to his mother, who states that her son “disappeared” after finding out his ex-girlfriend, whom he broke up with last week, is pregnant. Physical examination and urinalysis are both normal.
B) Dissociative amnesia
This patient’s sudden inability to remember autobiographical information in the context of an overwhelming event is consistent with dissociative amnesia, a retrograde autobiographical amnesia. Specifically, his traveling/wandering constitutes “dissociative fugue.”
Answer choice A: Depersonalization/derealization disorder, is incorrect. Patients with this disorder feel persistently and/or recurrently detached from reality. However, unlike individuals with dissociative amnesia, these patients can recall autobiographical facts.
Answer choice C: Dissociative identity disorder, is incorrect. This disorder is characterized by the fragmentation of an individual’s identity into two or more parts. Although autobiographical deficits can occur, they are specific to each distinct identity. This patient’s complete lack of autobiographical knowledge is more consistent with dissociative amnesia.
Answer choice D: Malingering, is incorrect. This patient’s confusion in the context of an overwhelming event is unlikely to be malingering, as there is no evidence of secondary gain for his condition.
Answer choice E: Transient global amnesia, is incorrect. Transient global amnesia is an acute anterograde amnesia that is self-limited (typically resolving in less than 24 hours). Patients with transient global amnesia often ask repetitive questions and have intact autobiographical memory.
Key Learning Point
Dissociative amnesia is a sudden, retrograde, autobiographical amnesia that is typically triggered by an overwhelming event. Transient global amnesia, by contrast, is anterograde and does not impact autobiographical memory.
