A small number of people who trip on psychedelics can develop hallucinogen persisting perception disorder (HPPD), a very rare and not a very well understood condition where people experience recurring or ubiquitous flashbacks.
The symptoms associated with HPPD vary; it can cause irreversible perceptual distortions, emotional and psychological distress, intense pain, depression, and suicidal thoughts.
HPPD: A Lifelong Trip
HPPD affects between one to five percent of people who use LSD, although the actual number is impossible to calculate without better data.
The disorder was first published in 1986 by the American Psychiatric Association’s Diagnostic & Statistical Manual of Mental Disorders, 3rd edition, revised (DSM-III-R).
The most recent edition of the DSM-5 manual says that patients must meet several different criteria to be appropriately diagnosed with HPPD:
- The symptoms are not due to a separate mental disorder or medical condition.
- People must reexperience perceptual symptoms they had while under the influence of LSD.
- The symptoms to the patient must cause overwhelming distress or impairment in work, social, or other important places of functioning.
What are the Differences Between HPPD and a Flashback?
Mostly duration and frequency.
A 2017 study published in Frontiers in Psychiatry showed that while a flashback is mainly reported to be episodic and infrequent, HPPD is long-lasting and persistent.
A 2014 study published in the Israel Journal of Psychiatry and Related Sciences demonstrated two types of HPPD.
The first type of HPPD I is the “flashback type,” where it is often short-term and not distressing, gentle, and it is a reversible state along with a pleasant effect.
The harshness of HPPD I differs, where some describe their minor flashbacks as annoying, whereas others say it is like having a “free trip.”
HPPD II is a lot more severe condition. HPPD II is a condition that can be permanent. It is accompanied by vision distortions with other symptoms that show up on an irregular basis.
The symptoms typically involve palinopsia (afterimages effects), which is visons of haloes, trails, visual snows, etc., according to the 2017 study.
Other perceptions such as sounds are most often not affected. However, the visual phenomena were reported to be disturbing and uncontrollable. Symptomatology can include anxiety, depression, depersonalization, and derealization.
What Causes Flashbacks Associated with HPPD?
As of now, researchers and scientists alike do not know precisely what causes flashbacks, but they do have some ideas.
A popular hypothesis focuses on memory. As psychedelics may cause tremendously powerful and emotional experiences, making it possible that certain stimuli from the environment can prompt people of those experiences, as memory “transports” them back into the individuals’ mindset.
It is like how a soldier with post-traumatic stress disorder (PTSD) may suffer a flashback after hearing a loud, sudden noise such as fireworks or a car backfiring.
Another hypothesis incorporates how LSD acts in the brain’s visual processing center. It comprises the disinhibition of the visual management concerning the loss of serotonin receptors in inhibitory interneurons. It may be related to using LSD.
The main idea is that LSD changes how the brain understands visual stimuli. This may explain why people diagnosed with HPPD have difficulty “disengaging” from things seen around them. E.g., a stoplight may not be seen as an isolated red circle instead as a streak of a red light that stretches across their vision field; or a strobe light may not look like a light that flickers but a light that looks like it is on continuously.
It is also likely that some may be genetically predisposed to HPPD, and taking LSD is the key to unlocking the disorder. This may help clarify why people have developed HPPD taking only a single or moderate dose of LSD.
Thus, the main issues that cause HPPD are still unknown. As a result, there is no cure for HPPD, but some studies show that people suffering from HPPD reported enhancements in symptomatology after being prescribed benzodiazepines. Also, there is anecdotal evidence showing that fasting can help with aiding in HPPD.
Scientists have a strong sense of triggering “flashbacks” associated with HPPD. A study done by Dr. Abraham’s in 1983 listed the primary triggers, which include:
- A dark environment