Drug-induced amnesia

Drug-induced amnesia is amnesia caused by drugs. Amnesia may be therapeutic for medical treatment or for medical procedures, or it may be a side-effect of a drug, such as alcohol, or certain medications for psychiatric disorders, such as benzodiazepines. It is seen also with slow acting parenteral general anaesthetics.
Medical usage.
Amnesia is desirable during surgery, since a general anaesthetic should also give the person amnesia for the operation. Sedatives such as benzodiazepines, which are commonly used for anxiety disorders, can reduce the encoding of new memories, particularly in high doses (for example, prior to surgery in order for a person not to recall the surgery). Amnestic drugs can be used to induce a coma for a child breathing using mechanical ventilation, or to help reduce intracranial pressure after head trauma.
Researchers are currently experimenting with drugs which induce amnesia in order to improve understanding of human memory, and develop better drugs to treat psychiatric disorders and memory related disorders. People with Alzheimer's disease and other forms of dementia are likely to benefit. By understanding the ways in which amnesia-inducing drugs interact with the brain, researchers hope to better understand the ways in which neurotransmitters aid in the formation of memory. By stimulating rather than depressing these neurotransmitters, memory may improve.
The use of a drug to erase traumatic or unwanted memories used to be referred to as "science fiction." Holmes et al. (2010) commented that the media misrepresented two recent studies as research on "erasing" traumatic memories, but showed the fear response associated with stressful memory could be greatly reduced whilst the factual memory of the trauma remained intact. Similarly, Brunet et al. (2008) found that the people with chronic posttraumatic stress disorder who were treated with propranolol for a single day had a reduced response to existing trauma while retaining memory of the trauma. In the process of remembering, the memory needs to be restored in the brain. By introducing an amnesia-inducing drug during this process, the memory can be disrupted. While the memory remains intact, the emotional reaction is damped, making the memory less overwhelming. Researchers believe this drug will help patients with post-traumatic stress disorder be able to better process the trauma without reliving the trauma emotionally. This has raised legal/ethical concerns should drugs be found to have altered the memory of traumatic events that occur in victims of crimes (e.g. rape), and whether it is therapeutically desirable to do so.
Non-medical drug-induced amnesia.
Amnesia can result from a side-effect of prescription or non-prescription drugs. Both substance use and alcohol can cause both long-term and short-term memory loss, resulting in blackouts.
The most commonly used group of prescription drugs which can produce amnesia are benzodiazepines, especially if combined with alcohol, however, in limited quantities, triazolam (Halcion) is not associated with amnesia or memory impairment.
In mythology.
Nepenthe, literally named anti-sorrow, is a substance mentioned in the "Odyssey" given to Helen of Troy, said to originate from Egypt. Consumption causes sorrowful memories to be forgotten.