What are flashbacks?

Acute Flashbacks

Acute flashbacks are sensory or emotional experiences in which a person relives a past event or experience. Most flashbacks are spontaneous and triggered by a particular sight, sound, or smell. The person undergoing a flashback recalls sounds, smells, images, and feelings often more vivid than they were during the original event or experience. Acute flashbacks are unexpected and short lasting. In most cases, they are benign, pleasant, even comforting. In some cases, however, they are disturbing and can lead to psychotic episodes, severe depression, or schizophrenia.

Chronic Flashbacks

Hallucinogen persisting perception disorder (HPPD) is a chronic condition in which recurring flashbacks interfere with a person’s daily life. In mild cases, flashbacks occur infrequently. In extreme cases, flashbacks occur regularly and begin to distort a person’s perception of reality. HPPD is associated with the use of hallucinogenic drugs. Flashbacks can occur any time, from a day to a year after taking a hallucinogen.

HPPD flashbacks cause visual disturbances. The person suffering HPPD may see flashes of intense color; auras around people’s heads; dancing geometric shapes; images trailing moving objects; positive afterimages, in which objects remain in the brain after they have left the field of vision; or distortions in which objects appear larger or smaller than they are in actuality.

Trauma-related Flashbacks

Trauma-related, or nondrug-related, flashbacks were first described medically by doctors treating World War I combat veterans. These types of flashbacks are seen not only in combat veterans but also in other people who have experienced severe trauma, such as witnessing violent death. Flashbacks affect many persons with post-traumatic stress disorder.

Drug-related Flashbacks

Hallucinogens are the drugs most associated with flashbacks. LSD (lysergic acid diethylamide, or acid); psilocybin in certain mushrooms; and PCP (phencyclidine, or angel dust), originally an anesthetic, are the main hallucinogenic, or psychedelic, drugs. By far, LSD is the most commonly used and studied psychedelic.

During LSD flashbacks, users experience an abbreviated version of an earlier drug trip, or experience, without taking the drug. Many users report that the flashbacks are even more intense than the original trips. The flashbacks can be isolated or recurring, brief or drawn-out, pleasant or disturbing, and benign or damaging. Because LSD flashbacks usually appear suddenly, without warning, they can disrupt a person’s daily routine and lead to unpredictable behavior.

Chronic LSD users are more prone to flashbacks than occasional users. People with an underlying emotional problem and people highly susceptible to suggestion also are more prone to flashbacks than healthy users. Even emotionally healthy people who have used LSD only once or twice can experience flashbacks more than one year after taking the drug.

Causes

Scientists do not fully understand the biochemical processes through which hallucinogens affect the mind and body, and they do not know the causes of LSD flashbacks and HPPD. Research suggests several theories for flashbacks.

First, drugs can remain stored in body fat and in some organs—lungs, kidneys, liver, brain—long after they are taken. When the body burns fat during strenuous activity, the drugs might enter the bloodstream, causing the person to experience some of the drug’s effects. Second, LSD might have damaged the brain, causing it to send incorrect signals. Third, LSD may have changed the way the brain functions and processes information, which may account for the accompanying visual disturbances. Another theory holds that flashbacks have nothing to do with psychedelic drugs, but that flashbacks are naturally occurring altered states of consciousness that are not understood and, consequently, mislabeled or misinterpreted by drug users.

Triggers

Although scientists do not know the causes of flashbacks, they are reasonably sure of certain triggers. Common flashback triggers include physical or mental stress; physical or mental fatigue; lack of sleep; marijuana or alcohol binging; the use of certain prescription drugs, including antidepressants; and mild sensory deprivation. People sometimes deliberately induce mild sensory deprivation to alter their consciousness or to deeply relax. To induce mild sensory deprivation, a person might focus intensely on one particular sound, blocking out all other background sound, or might stare at a solid-colored surface without blinking for an extended period.

Treatment

No specific treatment exists for flashbacks. Doctors have prescribed certain medications, such as antiseizure drugs, for people suffering HPPD. However, the effectiveness of these drugs remains debatable because of the unpredictability of flashbacks and because of the uncertainty of their cause. Treatment for trauma-related flashbacks generally follows the protocols for treating mild mental disorders: talk therapy or other forms of psychotherapy.

Bibliography

Baggott, Matthew, et al. “Abnormal Visual Experiences in Individuals with Histories of Hallucinogen Use: A Web-Based Questionnaire.” Drug and Alcohol Dependence 114 (2011): 61–67. Print.

“Hallucinogens: LSD, Peyote, Psilocybin, and PCP.” 18 Feb. 2012. Web. http://www.drugabuse.gov/infofacts/hallucinogens.html.

Heaton, Robert. “Subject Expectancy and Environmental Factors as Determinants of Psychedelic Flashback Experiences.” Journal of Nervous and Mental Disease 161 (1975): 157–65. Print.

Lerner, Arturo, et al. “Flashback and Hallucinogen Persisting Perception Disorder: Clinical Aspects and Pharmacological Treatment Approach.” Israel Journal of Psychiatry and Related Sciences 39 (2002): 92–99. Print.

Myers, Lin, Shelly Watkins, and Thomas Carter. “Flashbacks in Theory and Practice.” Heffter Review of Psychedelic Research 1 (1998): 51–57. Print.