What is amnesia Putting it simply amnesia is when someone cant remember things they have stored in their memory.
Types of amnesia Anterograde Retrograde Transient global Traumatic Alcohol induced Hysterical Childhood Source
Anterograde amnesia This occurs when the person cannot remember new info It is caused by brain trauma(a head injury) The person can remember things before the injury happened
Retrograde amnesia Retrograde is kind of the opposite of anterograde amnesia because victims can remember normally after the trauma.
Transient global amnesia In this cause the person for temporary loss of all memory they have a severe anterograde amnesia
Traumatic amnesia This is caused by a head injury such as a car accident they might go into a coma. This is usually temporary and sometimes indicates a concussion.
Wernike-Korsakoff's psychosis This is caused by alcohol abuse and gets gradually worse over time
Hysterical (fugue) amnesia This very rare circumstance is when someone wakes up and forgets their identity. They cant recognize their reflection. Their ids, drivers license, and credit cards are meaningless to the victim of this amnesia. They usually remember their identity over the course of a few days.
Childhood amnesia (infantile amnesia The victim of this amnesia cannot recall events from their childhood.
Source amnesia In this case the victim can remember the info but not the source.