Hallucinogen Persisting Perception Disorder (HPPD): Causes, Symptoms, & Treatments

What Is HPPD?

Hallucinogen Persisting Perception Disorder (HPPD) is a rare condition that involves episodes where you feel as though you’re tripping, even though you have not taken any psychedelic drugs recently. There are two different types of HPPD: type 1 and type 2. Type 1 HPPD is considered much less serious than type 2 and usually remits independently without treatment.^{1, 3}

It’s estimated that about 5% of people who try a psychedelic drug experience an HPPD flashback. HPPD has been reported most often following the use of LSD but has also been linked to mescaline, ketamine, MDMA, psilocybin, Ayahuasca, and even cannabis.^{3, 4}

The main symptom of both types of HPPD is psychedelic flashbacks, where people experience the same kinds of hallucinations as they did when tripping. HPPD flashbacks can occur weeks, months, or even years after taking a psychedelic drug.^{3, 4} Sometimes, the flashback is triggered by something you experience, and other times, there is no identifiable trigger.^{5, 6}

The most common symptom of an HPPD flashback is a change in visual perception, including seeing more intense colors, shapes, or “trails and tracers” of light when an object is moved.^{1, 3, 4} Some people also experience dissociative symptoms during an HPPD flashback, including feeling disconnected from themselves, their body, or their experiences.¹ For most people, these flashbacks will only last a few seconds or minutes before passing.⁴

Type I HPPD

Type I HPPD is usually considered benign and temporary. People with this condition have at least one psychedelic flashback, but these episodes don’t become severe or frequent enough to cause many problems or impairments.^{1, 3} While having an HPPD flashback can be distressing, most people with type 1 HPPD will find that their flashbacks lessen over time, even without formal treatment.^{2, 3, 4}

Type II HPPD

Type II HPPD involves the same kinds of flashbacks as type 1, but they tend to be more frequent, severe, and distressing for people. The flashbacks can begin at any point after a person has used a psychedelic drug, but in type II HPPD, they tend to worsen instead of lessen over time. Most people with type 2 HPPD require professional treatments like medication to manage their symptoms, and may struggle with long-term episodes of HPPD symptoms.^{1, 3}

What Is a Flashback?

A flashback is a vivid memory usually accompanied by the strong feeling of reliving an experience from your past. During an HPPD flashback, people can experience some or all of the same sensations and feelings as when they took psychedelics, including changes in their perception, thinking, and emotions.^{1, 3, 4} Most of the time, this involves visual hallucinations like seeing colors, light, shapes, or objects moving or behaving differently than normal.^{1, 4}

For example, people who have PTSD flashbacks feel as though they’re reliving a traumatic experience and often report being able to hear, smell, and see things in their memory as if they’re happening right now. When it’s a pleasant memory, you may not mind the vivid nature of a flashback. When it’s an unpleasant memory, a flashback can trigger the same kinds of fear and distress as you experienced during the original event. This also applies to HPPD flashbacks, which some people enjoy, and other people feel frightened and disturbed by.⁴

Similar to other kinds of flashbacks, people having an HPPD flashback are aware afterward that the experience wasn’t real. Being able to distinguish between something “real” and “imagined” is one of the key differences between a flashback and a delusion (an irrational belief someone believes with strong conviction). Flashbacks are often linked to dissociation when a person becomes detached from their body, surroundings, or experiences.¹

What Are Common HPPD Symptoms?

HPPD is not a well-understood diagnosis. Part of the confusion about HPPD is that the symptoms do not follow a predictable pattern. Because each individual responds a little differently to psychedelic drugs, the symptoms of HPPD also vary widely. During an HPPD episode or flashback, it’s possible to experience any of the cognitive and emotional changes that occur after taking a psychedelic drug. Most of the time, this includes changes in your visual perception that last only for seconds or minutes before going away on their own.^{2, 4}

Visual disturbances of an HPPD flashback can include:^{1, 4, 7, 8}

• Floaters: seeing spots that drift in the front of the field of vision
• Trails & tracers: seeing trails or traces of light or color when objects move
• Halos & auras: seeing, feeling, or sensing light, color, or energy around objects
• Color perception: seeing more or less intense colors
• Synesthesia: “seeing” music, “feeling” colors, or similar perceptual anomalies
• Fragmentation: seeing images or objects “dissolve” or disintegrate
• Aeropsia: seeing grains or particles of air
• Geometric hallucinations: seeing odd shapes and patterns
• Afterimages: seeing a lingering image of something

Dissociative symptoms of an HPPD flashback can include:^{1, 4, 7, 8}

• Depersonalization: Depersonalization is having an out-of-body experience of feeling disconnected from yourself, your thoughts, feelings, or experiences
• Derealization: Derealization is losing touch or feeling detached or distant from reality, losing track of time, or feeling like you’re in a dream
• Flashbacks: Having vivid memories from the past that feel real and as though they’re happening now

Emotional changes and mood-related symptoms of HPPD can include:

• Feelings of fear or anxiety that may escalate into a panic attack
• Feelings or fears of losing control
• Feelings of depression or sadness
• Feelings of distress or concern about HPPD symptoms
• Feeling as though things are robust, bizarre, or “off” in some way

HPPD flashbacks can be triggered by something happening inside or around you, or they can also happen randomly and seemingly without any trigger. Most people do not experience HPPD flashbacks right after taking psychedelics. Usually, there is a latent period of months or even years after taking a drug before the flashbacks occur. It’s possible to develop symptoms of HPPD after using a psychedelic drug just once or after several years of recreational use.^{1, 2, 3, 4, 8}

There also may be differences between the symptoms associated with the onset of type I HPPD vs. type II HPPD. For example, most people with type 1 HPPD report less intense “auras” and flashbacks that lessen and go away over time. People with type II HPPD symptoms are more likely to experience flashbacks that become more intense and frequent over time, and these may overlap with symptoms of prodromal schizophrenia.^{1, 2, 4, 9}

What Causes HPPD?

The exact cause of HPPD is unknown, but it has been established that certain populations are more at risk for developing this rare condition.^{8, 9} While anyone who has used a psychedelic drug at least one time can have an HPPD flashback, most people who experience them have a pre-existing mental illness or substance use disorder. Specifically, having a diagnosis of depression, anxiety, alcoholism, or psychosis does increase the risk of developing HPPD symptoms after taking a hallucinogenic drug. Low self-esteem, low resilience, and high emotional instability might also increase the risk for HPPD.²

The fact that mental illness and addiction overlap so much with HPPD is interesting and suggests that these conditions may present a genetic, neurochemical, or psychological cause for the condition. It’s been suggested that HPPD develops as a result of abnormalities in visual areas of the brain, which could be genetic or triggered by the use of certain psychedelic drugs.^{3, 8} No conclusive studies have found an answer to why some people develop HPPD while most people do not. One-time and frequent users can develop HPPD, which does not appear to be influenced by the type or dose of drugs consumed.^{2, 9}

Drugs That May Cause HPPD

Most current research suggests that only about 5% of people who experiment with psychedelic drugs will experience symptoms of HPPD. While most HPPD cases are linked to the use of LSD, no studies have given us clear evidence that HPPD risks are higher with LSD than with other drugs. However, some researchers have speculated that the risk of HPPD may be higher for synthetic (lab-created) psychedelics like LSD than with organic (naturally occurring) psychedelic drugs like psilocybin and mescaline.^{2, 3, 4}

Psychedelic drugs (taken alone or in combination with one another) that can lead to HPPD symptoms:^{1, 3, 8, 9}

• Lysergic Acid Diethylamide (aka acid or LSD)
• Psilocybin (aka magic mushrooms or shrooms)
• MDMA or MDA (aka molly or ecstasy)
• Ketamine (aka K or special K)
• Mescaline (aka peyote)
• PCP (aka angel dust or speed)
• Cannabis products (aka weed, marijuana, or synthetics like Delta 8 & 9, salvia, etc.)
• Alcohol (less common, but can occur especially when combined with other drugs)

In some cases, HPPD episodes are triggered by the subsequent use of one of the substances above. In addition to drug use, other people who have had an HPPD flashback report that environmental or situational triggers can cause an HPPD episode. For instance, moving from a well-lit place into a dark room, having sex, or seeing vivid and colorful images are commonly reported triggers for HPPD symptoms. Some people also say stress and mental health symptoms can worsen HPPD symptoms.^{3, 4, 6, 8}

How Common Is HPPD?

It’s estimated that only about 5% of people who have tried psychedelic drugs develop HPPD.^{1, 2, 9} While it is an uncommon disorder, it’s also possible that HPPD symptoms are underreported, meaning it’s possible that HPPD could be slightly more common than experts think. Some potential reasons for underreporting could include reluctance to disclose prior substance use, fear of legal or career consequences, or a mild or temporary case of HPPD flashbacks and symptoms. According to the research, someone experiencing HPPD flashbacks has a 50% chance of their symptoms resolving on their own, without any need for professional treatment.^{2, 3, 4}

HPPD and Co-Occurring Conditions

The majority of people who develop HPPD struggle with a pre-existing condition like depression, anxiety, or addiction. While researchers don’t know for sure, many suspect these conditions act as a predisposition or vulnerability for HPPD.^{2, 3, 4}
In more severe cases of HPPD, the symptoms people experience resemble psychotic symptoms typically seen in the prodromal phase of schizophrenia. These include changes in mood, perception, thinking, and behavior like depression, anxiety, memory problems, hallucinations, and odd behavior.⁹ Depending on the type of HPPD, these symptoms may be temporary or long-lasting and cyclical in nature.^{4, 6}

Some of the conditions linked to HPPD include:^{1, 2, 3, 9}

• Major Depressive Disorder
• Bipolar disorder
• Anxiety disorders
• Panic disorder
• Psychosis and schizophrenia
• Alcoholism and addiction

In people diagnosed with another pre-existing mental health or substance use disorder, HPPD can trigger a worsening of symptoms. For example, people with co-occurring depression may find their depression worsens, and people with co-occurring anxiety may experience more anxiety or panic attacks. People with substance use disorders and addictions may self-medicate with recreational drugs or alcohol, which can exacerbate their symptoms and their addictions.^{1, 2, 4}

How is Hallucinogen Persisting Perception Disorder Diagnosed?

Diagnosing HPPD usually involves an appointment with a licensed mental health or addiction therapist or medical professional. During this appointment, you’ll be asked a series of questions about your medical and mental health history, past and current substance use, and personal life that will be used to determine your diagnosis.

Depending on where you’re seeking treatment, this may occur in a doctor’s office, psychiatric clinic or hospital, or therapist’s office. Most of the time, professionals will determine your diagnosis by gathering your information in an appointment. Less commonly, you may be referred to a specialist or asked to complete other diagnostic labs or tests to rule out another condition or confirm your diagnosis.

Getting Help for HPPD

Because a history of psychedelic use is needed to consider a diagnosis of HPPD, it’s really important to be honest about any prior substance use when seeking help for HPPD symptoms. Giving specific details (when possible) about the types of drugs you’ve used, when you last used them, and how much and how often you used them is necessary to receive an accurate diagnosis.

While many people are hesitant to open up to a professional about illegal or recreational drug use, it’s highly unlikely that this information would be shared with anyone else. The only exceptions are if you are a minor, if you are placing yourself or others in immediate danger, or if the professional is mandated to share information about your treatment with someone else (i.e., a probation officer, judge, doctor, or CPS worker).

HPPD Treatment Options

There isn’t just one type of treatment proven to help people struggling with HPPD visuals, flashbacks, dissociation, or other symptoms. Because many people find their symptoms lessen and resolve on their own with time, it’s also important to note that treatment isn’t always indicated for HPPD symptoms.^{2, 3, 4, 9} Professional treatment for HPPD is recommended in situations where HPPD symptoms and flashbacks are intense, frequent, or interfering with your ability to function.

At this time, there haven’t been specific types of psychotherapy found to help with HPPD symptoms. Still, therapy is usually recommended to anyone prescribed medication for a mental health disorder, meaning it’s still a good idea to consider including it in any HPPD treatment plan. There is some research that suggests electroconvulsive therapy (ECT) and Repetitive Transcranial Magnetic Stimulation (rTMS) could help reduce visual hallucinations in people with HPPD.³

Most HPPD research recommends pharmacotherapy (or prescription medications) as a frontline treatment for HPPD.^{6, 9} Depending on the type of HPPD (type 1 vs. 2) and how the person’s symptoms progress, medication may only be needed short-term.^{1, 3} More severe symptoms and courses of HPPD may require longer courses of medication to manage. A variety of different kinds of prescribed medications have been suggested for HPPD.

The medications most commonly used to treat HPPD include:^{2, 3, 6, 9}

• Benzodiazepine medications like Xanax or Clonazepam
• Antiepileptic drugs like Lamotrogine or Gabapentin
• SSRI antidepressant medications like Sertraline
• Opioid agonist drugs like Naltrexone
• Antipsychotic medications like Haloperidol or Risperidone
• Beta-blockers like Propranolol

Self-Care for Managing HPPD Symptoms

If you suspect you are experiencing HPPD flashbacks, it’s a good idea to keep a log of your symptoms to track over time. At the onset, it’s difficult to know whether HPPD symptoms will develop into type I HPPD, type II HPPD, or resolve on their own. Keeping a written log of your episodes can help you track your symptoms and gather data to share with a medical provider.

Here are some tips on how to cope with HPPD symptoms and flashbacks:

• Keep a written log to track symptoms: Start a journal or log to record the date, time, and specific symptoms you experience, and use this to record all of your suspected HPPD symptoms.
• Compare your symptoms to past psychedelic trips: HPPD symptoms vary from person to person but almost always mimic the experience of prior psychedelic trips, which can give you clues about whether you’re experiencing HPPD or something else.
• Identify ‘early’ signs of HPPD flashbacks: Many people who have HPPD flashbacks describe having a strange feeling right before they have a psychedelic flashback. Paying attention to what the first feelings and changes in perception are can help you better predict and manage HPPD episodes and flashbacks.
• Take a break and go somewhere safe: When HPPD symptoms begin, being in a safe, private, and conducive space can help ease anxiety and distress. If possible, try to catch symptoms early and get in a safe setting before they fully kick in.
• Use mindfulness tactics to avoid dissociation: Because flashbacks are a form of dissociation that detach you from the here and now, grounding and mindfulness techniques can sometimes lessen or even prevent them from happening. Paying attention to your surroundings or taking a few deep breaths can be a good way to practice these skills.
• Use a phrase, object, or image to anchor yourself in reality: Sometimes, it’s possible to prevent dissociative flashbacks by choosing one object, phrase, or image (mental or real) to bring yourself back to reality. For example, you could repeat a certain comforting mantra, hold an object in your hand, or fix your attention on something in your environment.
• Practice regular self-care to manage stress levels: Stress can trigger several health and mental health-related issues and may even play a role in the onset of HPPD symptoms. Regular self-care involves healthy routines and activities that reduce stress and help you feel more emotionally stable and balanced, boosting your overall mental well-being.
• Avoid recreational substance use: Because HPPD is linked to the use of mind and mood-altering drugs, it’s a good idea to steer clear of drugs and alcohol until your HPPD symptoms stop. This includes alcohol, marijuana, and even legal substances like caffeine and nicotine if you suspect they influence your mood or mindset.
• Make an appointment with a licensed professional: If your HPPD episodes worsen or persist, it’s a good idea to make an appointment with a licensed medical, addiction, or mental health specialist to get a formal diagnostic assessment and explore options for treatment. Bring your log with you to provide the most accurate information about your symptoms, which will help ensure you get the correct diagnosis.