People have been taking acid since the 19th century, but we didn’t know its potential for flashbacks until the 1950s — shortly after Albert Hoffman synthesized LSD. And while research has shed some light on how psychedelics affect the brain, there’s still a lot more to learn when it comes to LSD flashbacks, their causes, and how we can treat them.
There are, however, a small percentage of people who have strange — and often debilitating — side effects that last for days or weeks after a hallucinogenic trip, and that’s where hallucinogen persisting perception disorder ‘HPPD’ comes into play.
What is an LSD Flashback?
LSD users have reported the reappearance of LSD-like sensory experiences, including visual abnormalities, on occasion for years. These episodes are usually brief and do not pose a threat. However, a subgroup of LSD users, and MDMA users, are plagued by persistent visual distortions long after their last hallucinogen session. While the sound of this (and sometimes the flashback itself) can be distressing, not all of them are, and some have even been reported as neither bad nor good.
Symptoms of an LSD Flashback
According to the Visual Phenomenology of the LSD Flashback by Dr. Henry David Abraham, the most common symptom is visual distortion, including:
- Acquired color confusion
- Pareidolia
- Macropsia or micropsia
- Geometric phosphenes
- Difficulty reading
Note: even though they’re the most common, not all symptoms are visual. In a 1970 study called Analysis of the LSD Flashback, LSD flashbacks were categorized into three main categories: perceptual, somatic (bodily), and emotional.
What is HPPD?
HPPD is a rare and poorly understood syndrome in which people experience omnipresent or repeating flashbacks after using psychedelics. Unlike flashbacks, they may not subside for months, years, or even at all. This can cause significant anxiety and terror in those who suffer from it, and negatively impact everyday tasks like reading or driving. HPPD can induce acute pain, lasting perceptual abnormalities, emotional and psychological suffering, and even suicidal thoughts.
In the current edition of the Diagnostic & Statistical Manual of Mental Disorders, there are three main criteria for diagnosing HPPD:
- Presence of hallucinations after the cessation of the inducing substance
- Significant distress in occupational and social spheres
- The symptoms cannot be attributed to any other disorder or medical condition
So what’s the difference between a flashback and HPPD?
Simplified answer: mainly duration and frequency. Here are a few expert opinions:
- According to Frontiers in Psychiatry, “a flashback is usually reported to be infrequent and episodic, HPPD is usually persisting and long-lasting.”
- Flashbacks and HPPD: A Clinical-oriented Concise Review noted: “We have observed at least two different recurrent syndromes, the first Flashback Type we refer to as HPPD I, a generally short-term, non-distressing, benign and reversible state accompanied by a pleasant effect. In contrast, the second HPPD Type we refer to as HPPD II, a generally long-term, distressing, pervasive, either slowly reversible or irreversible, non-benign state accompanied by an unpleasant effect.”
There’s still a lot to learn on this subject, especially on what causes flashbacks and HPPD. There are theories that it’s related to memory, genetics, or even the brain’s visual processing center, but for the most part, it’s a big unknown.
Let us know what you think in the comments below!
