HPPD: What Is It, And What Are Its Symptoms?
Experiencing HPPD and looking for help? Please visit the Perception Restoration Foundation for more details and information on the HPPD, its effects and treatment options.
Hallucinogen persisting perception disorder (HPPD) is a possible risk of taking psychedelics. HPPD involves lasting or persisting visual distortions and/or effects after a previous psychedelic experience. The prevalence of HPPD is uncertain, as we will see, although it is rare.
HPPD is a condition in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). (This is the manual that psychiatrists use to diagnose mental health conditions.) According to the DSM-5, someone only has HPPD if other psychiatric or neurological conditions have been ruled out, and the visual disturbances cause the person distress in everyday life.
As with other mental disorders, it is typically emotional distress and/or disruptions to everyday life that warrant a diagnosis. This means someone may experience persisting perceptual effects after a psychedelic trip without having HPPD.
While this condition may be misunderstood, there is still a lot of valuable information about it that should be highlighted. Moreover, with psychedelics becoming more popular and accessible over time, it’s important that users are aware of this risk. After all, they can take steps to help deal with the symptoms.
Contents of this article
What Is HPPD?
Some Historical Context
Persisting visual changes following a psychedelic trip were recognized as early as 1954. LSD was already being studied at this time. The clinical psychologist M.J. Horowitz first introduced the term “flashbacks” in a 1969 paper. By this time, around 1-2 million Americans had already used LSD, and it was noticed that some people experienced recurrent intrusive images after the use of the drug.
The term “flashback” is still associated with psychedelic stigma — with the fear of psychedelics causing long-term damage. But the experience of a so-called flashback doesn’t mean you’ve ‘ruined’ your brain or mind.
Dr. Stanislav Grof described HPPD in his work LSD Psychotherapy (1978), based on his work with an estimated 4,500 patients from the 1950s to 1960s. He wrote that:
“[l]ong after the pharmacological effect of the drug has subsided, the patient may still report anomalies in color-perception, blurred vision, after-images, spontaneous imagery, alterations in body image, intensification of hearing, ringing in the ears, or various strange physical feelings.”
Dr. Henry Abraham of Tufts first codified HPPD in 1983 after he had seen hundreds of patients reporting related symptoms since the early 1970s. The condition was first established as a syndrome in 2000, included in the revised fourth edition of the DSM (DSM-IV-TR).
HPPD occurs when people take drugs — including (and especially) psychedelic drugs – and report significant, distressing changes to how they perceive the world. HPPD, despite the focus on perceptual changes, can sometimes involve changes to thoughts and feelings once the drugs have worn off.
These changes may be constant. They may then be more significant according to certain triggers, such as sleep deprivation or the use of drugs such as caffeine and cannabis. In other cases, HPPD symptoms can take effect in sudden episodes.
The perceptual changes include things like ‘visual snow’ (or static), after-images, trails, geometric phenomena, light sensitivity, and more classic psychedelic visuals.
While not distressing for everyone, these perceptual changes can cause a high degree of distress for some people. It’s when people are seriously bothered by the symptoms that they may be diagnosed with HPPD.
In cases where distress is not reported, an alternative label can be used, such as post-drug perceptual changes (PDPCs) or post-psychedelic perceptual changes (PPPCs).
After a period of intense initial distress, many people with HPPD learn to live with the visuals and return to normal life. If appropriate steps are taken, then visuals tend to reduce by themselves over time. They may also disappear one day entirely.
The disorder usually resolves in a few weeks to several months, though more severe cases have reported life-long and greatly impairing symptoms. Even if the visuals do not decrease, you can still treat the distress that defines the HPPD, allowing you to live normally. Many people learn to reframe the perceptual changes as sources of enjoyment.
HPPD is a non-psychotic condition (it may sometimes be wrongly diagnosed as substance-induced psychosis). However, many people with HPPD also experience depersonalization/derealization disorder (DP/DR). Depersonalization refers to the feeling of being detached from your body and thoughts while derealization is the sense that the world is unreal.
The Two Types Of HPPD
In the current literature, there are two types of HPPD:
- Type 1: Where changes occur in temporary episodes
- Type 2: In which changes appear as a regular feature of everyday perception, which can vary according to certain triggers
Type 1 would align with the notion of a “flashback”, which is when people feel like they’re experiencing psychedelic effects again, often in unpredictable bursts. For those with Type 1 HPPD, a particular psychedelic experience can be entirely re-experienced — both cognitively and perceptually.
HPPD is a complex, under-researched, and highly subjective condition. Nonetheless, people tend to report similar HPPD symptoms. These include the following visual phenomena:
- ‘Visual snow’: when your field of vision is coated with small, grainy dots like the static of a detuned TV.
- ‘Haloes’ and ‘starbursts’: when objects have a bright ‘halo’ or ‘aura’ ring around them. There might also be concentric colored rays around light sources.
- ‘Trails’: when an object moves, a trail of faint replicated images follows it.
- ‘Ghosting’: a whitish, ‘ghostly’ hue can surround objects and text.
- ‘After-images’: when the outline or silhouette of an object is seen on a surface after looking away.
- Intensified ‘floaters’: most of us can see ‘floaters’. These are the small squiggly lines and shapes that sometimes appear in our vision. With HPPD, however, floaters can become more visible, disturbing, and irritating.
- Enhanced hypnagogia and hypnopompia: These are the visions people see between waking and sleeping, and upon waking from sleep, respectively.
- Blue field entoptic phenomena: The appearance of tiny bright dots moving quickly along squiggly lines in the visual field. These are especially apparent when looking into bright blue such as the sky.
- Changes to size and depth perception: Things can seem smaller, ‘at-a-distance’, larger (so-called ‘Alice in Wonderland syndrome’), or possess a two-dimensional quality.
- Assorted psychedelic effects: Fractal kaleidoscopic patterns; faces; ‘breathing’ walls; moving, ‘wavy’, or shaky text; intense closed-eye visuals; or flashing and strobing lights.
People with HPPD may report other, non-visual changes, including:
- Physical effects, such as head pressure, acute neck pain, unequal pupil sizes, and muscle twitches
- Tinnitus and ringing of the ears
- More intense dreams
- Auditory changes
- Confused and unclear thoughts, including ‘brain fog’
- Anxiety, depression, and panic
What Causes HPPD?
The way that HPPD develops is not understood very well. What we do know is that many kinds of drugs can lead to the onset of symptoms (and not just psychedelic ones).
Drugs That Can Result In HPPD Symptoms
People have reported HPPD symptoms following the use of:
- DMT (including ayahuasca)
- Dextromethorphan (DXM)
- Diphenhydramine (DPH)
- A host of novel psychoactive compounds, many of which are similar to classic psychedelics
- Psychiatric medications (e.g. SSRIs, antipsychotic drugs, or while withdrawing from benzodiazepines)
The use of LSD seems to be the leading cause of HPPD compared to other drugs. It is unclear if this is because LSD has been historically the most commonly-used psychedelic, or if there is something special about the LSD experience or its effect on the brain.
Someone may report HPPD after only a single, low-dose experience with a tested drug, including even a microdose. Some report it after a handful of trips, while others don’t experience it until after many more.
Based on his clinical work, Abraham suggested the HPPD population falls into three groups, possibly due to genetic differences. These are those who report the onset of HPPD symptoms after 1-3 trips, the next group after 5-10, and the final group after 50+.
Recreational Use Of Psychedelics
HPPD symptoms occur almost entirely outside of clinical settings. There are several reasons why non-clinical environments would make HPPD more likely to occur.
Firstly, certain mental health conditions that are normally screened out in clinical trials could be correlated with visual changes.
Secondly, HPPD seems to be more likely following the abuse of psychedelics, frequently occurring in a recreational context. In contrast, participants in clinical trials only take two doses of a psychedelic, given a week apart.
Thirdly, 2018 research by John H. Halpern and Torsten Passie suggests that one’s risk of HPPD is increased if the psychedelic experience was challenging. This means the experience included intense reactions of panic, dysphoria, and anxiety. These so-called ‘bad trips’ are more probable in uncontrolled and unsupervised environments.
Lastly, HPPD may be more likely with ‘research chemicals’ sold as LSD or MDMA, including 25i-NMBOMe and synthetic cathinones (‘bath salts’).
We know little about how HPPD works and what exactly may be going on in the brain and beyond. The leading hypothesis, introduced by Abraham, relates the condition to a ‘disinhibition’ of the visual cortex.
Drugs like LSD decrease, or ‘disinhibit’, the filters of the brain’s visual cortex. This means that ‘noise’ that would otherwise be filtered out may remain in the field of vision. HPPD occurs, then, when these filters do not return to their pre-drug state. This may make HPPD akin to a form of ‘visual tinnitus’. As with patients who experience tinnitus, certain triggers may worsen symptoms.
Personality Risk Factors
Dissociative personality factors may predispose people toward developing HPPD and DP/DR. A particular risk factor may be trait absorption, or a tendency to be preoccupied with internal mental images and lost in daydreams and fantasies.
How Common Is HPPD?
Perceptual changes may not be uncommon, but diagnostic HPPD is probably rare. Nonetheless, there is a lot of variation in estimates of the prevalence of perceptual changes and HPPD.
Preliminary estimates of perceptual changes from the 1960s (called “flashbacks” then) to the 1990s are wide-ranging: anything between 1 in 20 to even 1 in 50,000 people.
With modern research, we find more consistency.
A 2010 survey of 626 subjects found that 34 percent experienced moderate perceptual changes after using psychedelics, and 6 percent more extreme changes. Of the 40 percent total, 73 percent said the changes didn’t bother them, 24 percent said they’d rather not have them but could live with them, and 3 percent reported distress.
A 2011 survey of 2,455 psychedelic users found that up to three-fifths reported lingering changes, 25 percent in ways that seemed permanent, and 4.2 percent in ways that were so distressing the individuals sought clinical help.
However, you should keep in mind that these studies feature small sample sizes and can be prone to sampling bias. For example, if HPPD-specific surveys display on forums dedicated to HPPD, this is likely to result in more negative reports.
Those who use psychedelic forums are likely to have more psychedelic experiences than non-enthusiasts, which raises the probability of developing perceptual changes. On the other hand, psychedelic enthusiasts on these forums may be more likely to enjoy these perceptual changes than find them distressing.
How To Deal With HPPD Symptoms
One way to reduce the occurrence or severity of HPPD symptoms is to avoid certain triggers. These can include sleep deprivation, stress, or the use of drugs like cannabis, caffeine, MDMA, and classic psychedelics.
If you develop HPPD symptoms, it’s best to take a break from psychedelics and give the condition time to resolve itself. Given that fatigue can worsen HPPD, you should focus on sleep hygiene so that you get both quality, uninterrupted sleep, and enough sleep.
Many HPPD sufferers find that continuing to fixate on symptoms only raises their distress and how noticeable the perceptual changes are. Accepting the changes and continuing to live an active social life, rather than isolating yourself, is important.
Certain pharmacological treatments may be helpful in resolving symptoms, too. These include reboxetine (antidepressant), clonazepam (benzodiazepine), naltrexone (opiate receptor blocker), and clonidine (anti-hypertensive).
These medications can be useful as a short-term solution for those with severe, debilitating cases. However, you should be cautious about their use, especially benzodiazepines, which carry a higher risk of addiction.
Psychological treatments may also be helpful. These include counseling and psychedelic integration. A therapist or counselor may use an approach like cognitive-behavioral therapy (CBT) to help you address the anxiety, stress, and self-stigma associated with HPPD symptoms. As a result, both the anxiety and visual disturbances may resolve.
Given that distressing perceptual changes may be more likely after a challenging psychedelic experience, dealing with the material from that trip may lead to an improvement in HPPD symptoms. This might include processing unconscious material or reframing the experience in a more accepting and positive way.
In order to address the lack of knowledge about HPPD, a non-profit called the Perception Restoration Foundation is helping to fund, facilitate, and organize research in this area.