Overview
A flashback, as defined by the American Psychological Association (APA) in their online Dictionary of Psychology, has two definitions:
the reliving of a traumatic event after at least some initial adjustment to the trauma appears to have been made. Memories may be triggered by words, sounds, smells, or scenes that are reminiscent of the original trauma (as in a backfiring car triggering a flashback to being in combat). Flashbacks may be associated with posttraumatic stress disorder.
and,
the spontaneous recurrence of the perceptual distortions and disorientation to time and place experienced during a previous period of hallucinogen intoxication. Flashbacks may occur months or even years after the last use of the drug and are associated particularly with LSD.
History and Etymology
The observation that people could re-experience events of the past is incredibly old. Tablets from the Assyrian Dynasty of ancient Mesopotamia mention soldiers who seemed to see and hear the spirits of enemies they had killed in combat. Many Assyrians believed that this was a supernatural disease that was the natural outcome of war. Plutarch, an ancient Greek historian, described in The Life of Marius a Roman general who suffered from night terrors and what sound like flashbacks to previous battles. Ancient Sanskrit texts describe “Smaranajanya Manovikar” which can be literally translated as “memory-born mental affliction” in which someone repeatedly disturbed by memories of the past. In the Hindu epic Ramayana, the rakshasa (demon) Maricha was shot by an arrow fired by Rama, which he survived but was permanently traumatized by until he renounced his ways and moved to a secluded forest. Maricha describes seeing Rama everywhere, even in the shadows of the trees that resembled the bow he was shot with, and hearing any word that started with “Ra” triggered paralyzing fear in him as his mind went to “Rama.”
The roots of modern psychology’s explication of this notion of being “haunted by the past” can be traced to Pierre Janet and Sigmund Freud, both of whom observed something like “re-enacting” or “reminiscences” in people who had experienced trauma and could not recount a straightforward narrative about it. Army doctors in WWI and WWII often framed these as hallucinations or psychotic breaks rather than a distinct experience connected to trauma. Around the same time, the term “flashback” was being used in technical manuals describing an engine failure where fuel gases travel in reverse and flame is shot backward. In 1915, D.W. Griffith used the term “flashback” to describe a narrative device in his films that interrupted a sequence of events to suddenly shift backward in time to depict past events. The term picked up in the world of art criticism alongside the film industry’s growth, where it was then applied to plays and novels. Around the 1960s, it became slang that referred to recurring hallucinations that continued days or weeks after a trip on psychedelics.
By the time the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) was written, “flashback” was codified as a symptom of Post-Traumatic Stress Disorder (PTSD).
Commentary
I’ve sometimes remarked that the plight of someone experiencing frequent flashbacks in which memory and agency are both compromised is not too different than that of a chronic substance user who experiences benders. I’m not necessarily sure how appropriate or accurate the comparison is, but my own experiences reveal a degree of empathy to be found in the “episodes” that each may have.