Hallucinogen persisting perception disorder

In 1898, the English writer and intellectual Havelock Ellis reported a heightened sensitivity to "the more delicate phenomena of light and shade and colour" for a prolonged period of time after consuming the psychedelic drug mescaline. This may have been one of the first recorded cases of what would later be known as HPPD.[2]

According to a 2016 review, there are two theorized subtypes of the condition.[3] Type 1 HPPD is where people experience HPPD in the form of random, brief flashbacks. In addition, Type 2 HPPD is where people experience ongoing changes to their vision, which may vary in intensity.

HPPD is not related to psychosis due to the fact those affected by the disorder can easily distinguish their visual disturbances from reality. [4] The only certain cause of HPPD is prior use of hallucinogens. Some evidence points to phenethylamines carrying a slightly greater risk than lysergamides or tryptamines. There are no known risk factors, and what might trigger any specific disturbing hallucination is not known.[1] Some sort of disinhibition of visual processing may be involved.[5] It has been suggested MDMA (ecstasy) use with other drugs is linked to the development of HPPD.[6]

HPPD is a DSM-5 diagnosis with diagnostic code 292.89 (F16.983).[1] For the diagnosis to be made, other psychological, psychiatric, or neurological conditions must be ruled out and it must cause distress in everyday life.[1]

As of 2021 there is still no good evidence of any specific medicinal treatment as being commonly effective for HPPD. Some reports point to sedatives being helpful and stimulants and cannabis worsening symptoms.

Avoiding any additional use of psychoactive drugs (including cannabis and alcohol) from an early stage of the disorder seems to be an effective way for many sufferers to achieve recovery, as these substances apparently worsen the condition over time.

Some prescription drugs (Lamictal, clonazepam, keppra and others) have been known to relieve symptoms for some, but worsen symptoms or create dependencies for others.

Antipsychotic drugs and SSRIs have also been reported to help some people temporarily but worsen symptoms for others.

Some sufferers have reported benefits from prolonged water fasting, medications like NAC and Lithium, and from supplements like L-Tyrosine, Ashwagandha and lion's mane, although some users report lion's mane and Ashwagandha as having potentially negative effects or creating dependencies.

Sunglasses and talk therapy might also help those who are dealing HPPD, but in general it seems that maintaining sobriety from all psychoactive substances is still the best solution available for this condition, as it's been proven to naturally relieve the disorder over time.

The prevalence of HPPD was unknown as of 2018. Estimates in the 1960s and 1970s were around 1 in 20 for intermittent HPPD among regular users of hallucinogens. It is not clear how common chronic HPPD may be, but one estimate in the 1990s was that 1 in 50,000 regular users might have chronic hallucinations.[1]

In the second episode of the first season of the 2014 series True Detective ("Seeing Things"), primary character Rustin Cohle (Matthew McConaughey) is depicted as having symptoms similar to HPPD such as light tracers as a result of "neurological damage" from substance use.[7]

American journalist Andrew Callaghan, the host of the internet series All Gas No Brakes, revealed during a 2021 interview with Vice News that he has a HPPD diagnosis as a result of excessive psilocybin use at a young age. Describing his symptoms, he noted that he experiences persistent visual snow and palinopsia.[8]