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Hallucinogen Persisting Perception Disorder

December 17th, 2008

Hallucinogen Persisting Perception Disorder, HPPD, is a long lived problem arising from past use of strong hallucinogenic drugs. The majority of patients with HPPD report a prior use of lysergic acid diethylamide (LSD). Life LSD dose does not appear to increase the risk to developing HPPD. That is, I have seen some patients who have tripped on acid multiple times and then developed HPPD, and others develop the same disorder after one or two trips. I liken tripping on acid to playing Russian roulette, but using chemicals instead of bullets. Developing HPPD without ever tripping on acid can also happen, but in my experience this is quite rare, and suggestive of another disorder in the nervous system that needs medical attention.

The usual HPPD patient knows better than his doctors what is going on. The patients I see in consultation often have seen an average of six other medical specialists before they found their way to my office. This is probably because HPPD is a rare disorder, and not something that neurologists, psychiatrists, psychologists, and ophthalmologists usually encounter in training. Ironically these are the specialists most often consulted by the HPPD patient. Too often the first (and mistaken) clinical impression is that the patient has a psychosis. This can set treatment on a wrong path.

The majority of HPPD patients do not suffer from psychosis, or other signs of psychotic illness, such as auditory hallucinations and delusions. The disorder is for the most part a perceptual disorder in which visual information from the perceived world enters the brain but then cannot shut itself off. The result is lingering visual information, or a disinhibition of visual information processing, in the form of after-images, the trailing of images as they move through the visual field, flashes of light, and the formation of complex imagery on otherwise blank surfaces. Typical drawings from HPPD patients of what they see are shown on the right.

The first scientific description of the persisting visual phenomena described by LSD users may be found here.

Research in my laboratory later documented quite clearly that in the HPPD patient, when a visual signal from an image enters the brain, the signal stays around in consciousness longer than it does in the control subject who does not suffer HPPD. This finding has been found in three different studies of visual psychophysics. One finding, shown in Figure Five, was that LSD users see a flickering light as fused more often than non-users, because the eyes of the LSD user continues to see the light after it’s gone. For details click here.

A similar event occurred if a subject was exposed to bright light, and then tested for the ability to adapt to darkness. In this experiment, Dr. Ernst Wolf and I found that the dark adaptation of LSD users was reduced compared to non-drug controls because the LSD group could not mentally shut off the original light enough to see a tiny light when in the dark. See Figure 6.

This impairment could be important, for example, to persons needing night vision such as airplane pilots.

My colleague, Frank Duffy, and I also found characteristic abnormalities in the brain’s electrical activity in HPPD subjects, documenting that HPPD is a disorder which clearly takes place in the brain, and not simply in the imagination. Figures 7 and 8 below are examples of brain electrical activity maps (BEAMs) of an HPPD patient side by side with a group of normal individuals for comparison.

For scientific details please visit:

Categories: HPPD
  1. Jessica Keller
    April 22nd, 2009 at 21:36 | #1

    I am researching HPPD for a psychology 101 project and was curious about what kind of hallucinogens trigger this disorder. Is there more reports of Hppd occurring in those who use lysergic acid diethylamide than those who use psilocybin, mescaline, MDMA, phenylcyclohexl piperidine, or marajuana?

  2. May 26th, 2009 at 14:50 | #2

    I have had HPPD, Palinopsia, and Depersonalization for the past 23 years, since I was 17 years old, as the result of taking 1 hit of acid in my whole life during this time.

    I underwent many tests to find and cure the problem, but it was not detectable and everything checked out normal. These symptoms cleared up 4 times over the past 20 years for a minute or 2 each time. Then everything returned back to distorted again.

    At the time, 1994, no one heard of this so there was no information available about it. A few years ago an eye doctor I was suggested palinopsia, so I did more research and found out about HPPD, Palinopsia, and Depersonalization, and I have them all to a T! I also found a few articles in the J. Clin Psychiatry Journal that a few patients had the same symptoms and found cures using tegretol and Neurontin. I have tried these and they didn’t help me, except to relax.

    I’m so happy to at least know that someone out there knows about what it is and can describe it so perfectly. I used to try to explain to doctors, and still do, what I was experiencing and no one understand it.

    I also found an article on the Internet written by a Dr. Evans, from Texas I think, about Migraine Aura. This was the first to describe the symptoms of a millions dots, sensitivity to light, halos around objects, fluidity in static objects, visual snow, and grainy vision.

    I then found out about Migraine-aura.org online and read a case about a man named Victor in an article by Klaus Podoll, which described exactly the same things that happened to me and what I’m experiencing.

    So, now I’m writing to Mr. Abraham.

    If anyone can help me or knows of any cure. Please contact me at jamesphilliard@yahoo.com

    Best Regards everyone,

    James P. Hilliard

  3. August 13th, 2009 at 17:22 | #3

    Dr James:

    Thanks for your complex and personal post. I’m sorry to hear of your difficulties. The path of living with HPPD varies widely, but there is nothing that should stand in your way toward living a long and happy life with such a diagnosis. I say this having treated many patients over the last thirty plus years.

    I am not sure about the role of persistent migraine aura in your case. The use of a hallucinogen preceding the onset of symptoms, in the absence of classical migraine headaches, points more to the former than the latter. But it makes sense that there are many bad things that can happen to the brain to lead to an HPPD-like visual disorder without a person ever taking hallucinogens. For example, temporal lobe seizures can look like HPPD at times. Clearly, a consultation to review your case history with a doctor in your area knowledgeable about HPPD may be helpful.


    Dr. A.

  4. August 13th, 2009 at 17:27 | #4

    Jessica Keller :
    I am researching HPPD for a psychology 101 project and was curious about what kind of hallucinogens trigger this disorder. Is there more reports of Hppd occurring in those who use lysergic acid diethylamide than those who use psilocybin, mescaline, MDMA, phenylcyclohexl piperidine, or marajuana?

    Hi, Jessica:

    Although HPPD refers generically to the disordered associated with hallucinogenic drugs, it’s LSD, by far, which has had the strongest link to the disorder, compared to all the other drugs you’ve listed. I’ve seen cases of folks with HPPD from other stimulants, including psilocybin, mescaline, and even (rarely) patients on weed alone, or Ritalin. But LSD leads the pack as the most common cause of HPPD at this point in time.

    Dr. A

  5. S. Stevens
    October 7th, 2009 at 10:45 | #5

    Dear Dr. Abraham,
    Can you kindly e-mail me with a contact # where my doctor can speak with you. He needs info quickly in regards to HPPD and ketamine. My daughter is suffering with what we believe to be HPPD. as she has visual snow/static vision. It is a very complicated case and we are currently undergoing experimental treatment/study out of the USA. Any help you can give to the doctors here ASAP would be helpful. It is too lengthy to discuss in an e-mail as my daughter is currently involved in a protocol/study. Thank you for your urgent reply! S. Stevens

  6. Kyle
    October 29th, 2009 at 19:49 | #6

    Dr. A,

    I was wondering if you knew if nortriptyline effects visuals or hppd in an adverse way? It is used to treat chronic pain but falls under the anti depressant umbrella for some reason. I know ssri’s increase visuals but I was wondering about this one. Thanks.

  7. John
    November 20th, 2009 at 15:02 | #7

    Hi Dr. A,

    Following a period of LSD use, I developed a case of HPPD 13 years ago. I have seen an neurologist, and EEG reports have shown that I have abnormalities in my temporal lobe. Is there a difference between HPPD and temporal lobe seizures?

    Thank you!

  8. Aaron Palmer
    February 14th, 2010 at 04:17 | #8

    Dr. Abraham,

    I have had HPPD for 8 years now. I have been on many medications, such as Seroquel, Lexapro, Paxil, Buspar, etc. that have treated the underlying anxiety caused by HPPD.

    Have you ever had a patient successfully get rid of HPPD? What medications have you given patients that seem the most successful in treating HPPD?

    Thank You

  9. Denise LaChance
    June 5th, 2010 at 18:41 | #9

    Thanks for this information. I have had persistent “tracers” since fairly limited teenage (early 70′s) use of hallucinogentic drugs, primarily LSD. They seem to get worse when I am on strong doses of medications such as Sumatriptan and psychoactive medications. I have mentioned it to my physicians & gotten the response “never heard of that happening.” It hasn’t bothered me terribly, although I have wondered what it indicates about any long term effects of those drugs on my brain. I’m grateful for the Internet and the chance to confirm that this is something people who have used hallucinogenic drugs in the past experience, and that it does not necessarily mean that anything else is wrong.

  10. nigel sapheson
    August 24th, 2010 at 11:19 | #10

    I have been suffering from this for about 29 years from the age of 14 after 2 hits of LSD, it appeared on the first hit but came on strong after the 2nd and has remained since I suffer all the classic symptoms 24/7 alond with dp/dr but also once or twice a year since i suffer a type of flashback/delusional episode these have lasted up to 5 hours. I live in England on the south coast, and would love to volunteer for any studies that are going on with this, anything I can do to help the better understanding of this condition. So if you Dr Abraham know any studies taking place in England or if there is anyone reading this who knows dont hesitate to contact me.

    email : saphn@yahoo.com


    Nigel Sapherson

  11. ihsan
    September 10th, 2010 at 03:12 | #11

    hello there..
    i appreciate that you have written down all that doctor..
    but i do have a few questions..
    i am a 19 year old who just graduated from pilot school and will hopefully be working in the coming 6 months.. i have been doing cannibas for the past 2 years on daily bases.. and after that i tried magic mushrooms 5 times in a period of 6 weeks.. the first 4 times were light and it made me just love life.. but the last trip was very bad.. and my heart was beating so fast for 8 hours..
    after that day i was all good.. but after 4 days from that i started to feel like im not in reality anymore.. like something is wrong.. i was in fear all the time.. just wasnt myself anymore.. ive had painfull headaches but now they are gone.. reality seemed to come back to me after almost 2 weeks after.. not completely though..
    today morning i slept at 7 am and woke up at 11 am.. so i just had 4 hours of sleep.. ive also been sleeping that late for the past week but usually wake up late too.. so today i was walking around at a mall looking for a friend and just out of nowhere i started to feel dizzy and like my blood pressure just dropped and my heart started to beat fast again..just like before.. and reality is not as it used to seem anymore.. maybe its beacause im tired but i never used to be like that before.. its 2 am right now and i cant seem to sleep.. i really need some help.. i dont know whats going on.. but could this be some sort of hppd?..
    i would appreciate some help people..
    thank you
    future pilot ihsan abuhamad

  12. September 24th, 2010 at 15:36 | #12

    Dear Ihsan:

    I can’t think of a more dangerous combo than a pilot who has messed with hallucinogenic drugs. (Actually I can, but this one is bad enough.) While I can’t diagnose or treat folks over the internet, I can tell you that anyone with HPPD should not fly planes. It’s that simple. Visual function is critical, even in an age of instrument flight controls. One of the commonest symptoms of HPPD is “seeing the air.” I coined the term “aeropsia” to describe it. Some folks call it “visual snow.” Regardless of the name, the problem is that dark adaptation is severely impaired with this symptom. Imagine flying into a small airport at night looking for a familiar string of tiny points of light of a runway. Then try seeing that string of lights through a storm of visual dots swirling everywhere you look. You get the picture. Fortunately, nothing you’ve said sounds like HPPD. But if you continue to try hallucinogens and fly planes, let me know what airline you work for so that I can steer clear. My advice is to talk to a local psychiatrist to see if appropriate medication can make you feel better.

  13. September 24th, 2010 at 15:58 | #13

    Dear Aaron:

    I apologize for my slow response, a result of being less than sophisticated in the ways of websites. Your question is an important one. Unfortunately, there have been no proven breakthroughs in the drug treatment of HPPD in the last fifty years. We continually look for them, and several are actively being tested in clinical trials. For an agent to be useful, obviously it has to work, but it also has to be safe. The class of meds that comes closest so far are the benzodiazepines, mostly diazepam and clonazepam. Under medical supervision they are both helpful and safe. They seem to work by reducing the anxiety that makes HPPD symptoms worse. They do not directly reduce symptoms, though we have publisehd experimental evidence that midazolam, only given intravenously, can significantly reduce symptoms, if only for a few minutes. Thus the work goes on. If you have any interest in knowing more about the experimental sides of treatment, please contact me.

  14. September 24th, 2010 at 16:04 | #14

    Dear John:

    Again, accept my apologies for a slow response. Temporal lobe epilepsy is not HPPD. Yet there seems to be overlap. My colleague, Frank Duffy, and I found regions of overly active brain areas in HPPD subjects without seizure disorders, and the areas most involved were the occipital and temporal lobes of the brain- areas given to visual information processing. Logically one would think that treating the TLE would also treat HPPD. Sadly that does not seem to be the case. It may be that both disorders involve the temporal lobes, but in different ways.

  15. September 24th, 2010 at 16:09 | #15

    Dear Kyle:

    I am sorry to be getting to you so late in the game, but am still learning how to rassle with my website. While a number of folks have claimed that SSRIs make HPPD worse, I haven’t seen good data to that effect. I treat depressed patients who have HPPD with SSRIs and have so far seen no problems. Nortriptyline is an old but excellent drug, less often used because of its side effects. Again, I know of no evidence it causes problems with HPPD. In one of our studies we asked HPPD patients what made it worse. Only 1% said it was an antidepressant like nortriptyline.

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