Many hallucinogenic drugs can have a powerful effect on your mind and consciousness. Some increase your empathy and sociability. Others can cause you to hear and see things that aren’t really there. Some hallucinogens and psychedelic drugs can have serious acute effects, but they may also leave you with after effects. People who use drugs like LSD and MDMA sometimes report seeing visual hallucinations months and even years later, even when they’re sober.
These psychedelic aftershocks are attributed to a cognitive disorder called hallucinogen-persisting perception disorder (HPPD). Flashbacks to the experience of taking a psychedelic drug can be pleasant or frightening, but either way, they’re disruptive. Some people experience constant visual anomalies that get in the way of their normal lives. Learn more about HPPD and how it can be treated.
What Is Hallucinogen-Persisting Perception Disorder?
Hallucinogen-persisting perception disorder (HPPD) is a mental health problem that can affect your visual and auditory perceptions. It’s a cognitive disorder, which means it causes abnormalities in brain function that can negatively affect your daily life. People with HPPD can experience recurring visual or auditory hallucinations after the use of a drug that causes hallucinogenic effects.
HPPD is commonly caused by the recreational use of psychedelic drugs like LSD or DMT. HPPD is more commonly known as a flashback or a psychedelic flashback. Although an HPPD flashback is distinct from flashbacks that people with a post-traumatic stress disorder experience, they have some similarities.
The flashbacks that HPPD causes can vary, but visual distortions, flashes of color, halos around objects, and size differences can occur. Flashbacks can be brief, minor disruptions in your day, but they can also be more disturbing. Disturbing flashbacks can significantly impact your life, lower your quality of life, and prevent you from pursuing your goals and responsibilities. HPPD flashbacks occur when you’re sober, not when you’re taking a drug that can cause psychedelic effects.
There are two types of HPPD that are determined by the kinds of hallucinations you experience. Type 1 involves short flashbacks at random times. They may be momentary flashes of color or other visual disturbances. They may be minor annoyances in your life, but persistent flashbacks can lead to disorder and stress in your life, even if they are momentary. Type 2 involves flashbacks that are more disturbing and disruptive. Visual distortions may be more consistent and last longer than in type 1.
Hallucinations that HPPD causes are different from ones that are caused by psychotic disorders or current hallucinogenic drug use. The key difference is that people who experience HPPD flashbacks are aware that the visual distortions and hallucinations they are experiencing aren’t real. Hallucinations that are caused by something like schizophrenia can cause a break from reality.
However, even if you know a hallucination isn’t real, it can still be frightening and disruptive in your life.
What Are the Types of Hallucinogen-Persisting Perception Disorder?
There are two types of hallucinogen-persisting perception disorder, but the disorder is understudied and poorly understood. The two subtypes are theoretical and may not perfectly describe your experience with HPPD. If you’re diagnosed with one of these types, it doesn’t mean you may not have experiences that are similar to the other type.
Type I is mild, and many people who experience it never feel the need to seek treatment. It may involve brief flashes of light or color that go away quickly. These flashes may appear randomly and rarely persist for very long. Type II is more intense, and it may cause more impairment in your life. Flashbacks may involve long-lasting vision changes and visual distortions. These flashbacks may persist constantly and can vary in intensity.
What Causes Hallucinogen-Persisting Perception Disorder?
Besides using a psychedelic drug at some point in your life, the risk factors for HPPD are unclear. Researchers don’t know what causes the disorder. The brain is complex, and even psychedelic drugs are poorly understood. Many of the people diagnosed with HPPD also have other psychological disorders that may contribute to the development of the disorder. Some people can use psychedelics for many years without ever developing HPPD symptoms. Others experience symptoms after one use of a psychedelic substance. Researchers have identified that HPPD is not caused by brain injuries, seizures, or other neurological disorders. Finding one of those factors after experiencing symptoms may rule out HPPD.
Experiencing a drug flashback after using psychedelic drugs doesn’t mean you’ll continue to experience them for the rest of your life. Some people only experience a single HPPD flashback, while others have more consistent symptoms.
What Are the Symptoms of Hallucinogen-Persisting Perception Disorder?
In psychology, a flashback causes you to relive something in your past. It’s more than a memory, and it may actually feel like you are there, experiencing something that you can remember. Flashbacks associated with HPPD may involve hallucinogenic symptoms that you once experienced when you took a psychedelic drug.
Flashbacks that trauma causes make you relive a traumatic event. Severe flashbacks can interrupt your current circumstances and make you feel detached from the world around you, which is called dissociation. HPPD flashbacks are different from other kinds of traumatic flashbacks. Still, HPPD flashbacks can be distressing or disruptive.
HPPD symptoms include:
- Visual snow. This refers to an appearance of snow or static that obscures your vision. This static may be similar to TV static.
- Intensified colors. Colors are brighter and more intense. The contrast between colors may be stark.
- Flashes of color. Momentary flashes of color are seen that may be triggered by colorful objects, lights, or sounds.
- Geometric hallucinations. You may see fractal patterns that aren’t there. Some people report seeing patterns similar to the kind depicted on Persian rugs.
- Movement in the corner of your eyes. You may see movement in your peripheral vision that isn’t actually there. When you look at the movement directly, it appears to have no source.
- After images. Also called palinopsia, after images are when objects leave trails in your vision, like visible echos. Images may linger in your vision after the original exposure to the image is over.
- Micropsia and macropsia. This is when objects appear larger or smaller than they actually are. It’s also called Alice in Wonderland Syndrome, which can also involve other visual distortions.
Are Drug Flashbacks Pleasant?
Flashbacks and intrusive thoughts that PTSD causes are always unpleasant and unwanted. However, drug flashbacks that HPPD causes will depend on the experience you had when you were taking the drug initially. In some cases, flashbacks to a euphoric drug experience can feel good. However, if you have an intense or frightening experience on a drug, you may re-experience those negative feelings when you’re sober.
Many hallucinogenic drugs don’t cause intense euphoric effects like other recreational drugs. For instance, opioids, depressants, and stimulants can have a significant influence on feel-good chemicals like dopamine, serotonin, and endorphins. Psychedelic drugs like LSD and DMT have some effects on dopamine and serotonin in your brain, and they may cause pleasant effects. However, they can also cause powerful hallucinations, intense emotions, and even frightening visions.
Your experience on a psychedelic drug can depend on many factors, like how you personally respond to the drug and your environment. Many psychedelic users call this “set and setting,” which refers to your mindset when you take the drug and the physical environment around you. People who are in a bad mood or in a loud, disruptive location may risk a bad trip, which is a negative experience while using a drug. In some cases, bad trips can be traumatic, like a nightmare that feels more real.
How Are HPPD Flashbacks Different?
HPPD flashbacks are often dominated by visual and perceptual anomalies rather than other aspects of hallucinogenic experiences. Other flashbacks may make you feel like your separation from your immediate situation and surroundings. Like flashbacks caused by PTSD, Type 2
HPPD is also associated with dissociative episodes, according to a 2018 study. The study suggests that flashbacks cause overactivation in certain brain pathways that worsen anxiety. Dissociation is associated with anxiety and maybe a function of your brain that allows you to distance yourself from distressing surroundings and circumstances.
However, unlike PTSD flashbacks, HPPD flashbacks typically aren’t traumatic. Still, HPPD II can be distressing and intense, which is similar to other flashbacks.
Whether you experience frightening drug flashbacks or momentary perceptual changes, random disruptions throughout your day can be distressing. Even if a flashback brings on a positive experience, random cognitive disruptions that you can’t control can get in the way of your daily activities. Longer-lasting flashbacks associated with type II HPPD are especially distressing. They can make it hard to concentrate on tasks, perform at work, and even drive in some circumstances.
How Is Hallucinogen-Persisting Perception Disorder Diagnosed?
If you’re experiencing disrupting symptoms like hallucinations and visual disturbances, it’s important to get an accurate diagnosis. Several disorders and medical issues can cause similar symptoms, and some are more serious than others. The first step in getting a diagnosis is to speak with your doctor. Medical exams and blood tests are a good place to start.
No medical tests can diagnose HPPD, but there are medical causes for a similar set of symptoms. Ruling out other possibilities like brain lesions or epilepsy can help narrow down your diagnosis. You may also need to see a neurologist for imaging to rule out physiological causes like tumors.
When you’ve narrowed down some of the potential diagnoses, your doctor or therapist may use the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to explore psychological causes. The DSM has three criteria for diagnosing hallucinogen-persisting perception disorder. The three signs of HPPD include:
- Re-experiencing changes in perception after you stop using a hallucinogenic substance like LSD or DMT. These perceptual changes can include geometric visuals, movement in the corner of your eye that’s not there, after images, changes in the sizes of objects.
- These symptoms of visual perception changes cause significant distress in your life, including social, occupational, or functional impairment.
- The symptoms can be explained more clearly by something else, like current drug use, other mental disorders, or medical conditions like brain infections.
Other Disorders with Similar Symptoms
Because there are so many potential causes for some of the perceptual anomalies, it’s important to rule out other possible causes of your symptoms. Here are some other mental and physical health issues that can cause hallucinations:
- Mood disorders. Mood disorders include depression and bipolar disorder, they typically cause symptoms related to low moods or mania, and they can also cause physical discomfort and fatigue. But extreme moods can cause delusions and other symptoms that are seen in psychosis. It’s possible that severe mood disorders could cause hallucinations.
- Schizophrenia. Schizophrenia is a disorder most closely associated with delusions and hallucinations. Psychosis can cause visual distortions that are similar to the symptoms of HPPD. However, someone with schizophrenia has a hard time distinguishing between reality and hallucinations.
- Epilepsy. Epilepsy is an important condition to rule out when you’re experiencing visual hallucinations and perception anomalies. Epilepsy can cause partial or complete seizures, which is when the neurons in your brain fire excessively. This can cause cognitive anomalies like hallucinations.
- Migraine. Migraines are a poorly understood problem, but they are also associated with perceptual changes. Visual changes are associated with migraine auras, a period that often comes before migraines. An aura can cause blurred vision, vision flickers, and a sense that the room is spinning. In some cases, visual and auditory hallucinations have been reported.
- Brain lesions. Brain lesions are other sources of hallucinations and visual disturbances. Damage to different parts of your brain can cause different symptoms. Lesions may affect the parts of your brain associated with vision and perception.
- Alcohol withdrawal. Acute drug use could cause hallucinations, but alcohol and other depressants can cause hallucinations when you stop using them abruptly. Alcohol withdrawal can cause delirium tremens, a condition that’s associated with severe confusion and overstimulation in the nervous system. Delirium tremens gained nicknames like “seeing pink elephants” because of their association with hallucinations.
How Common is Hallucinogen-Persisting Perception Disorder?
HPPD isn’t well-studied or understood, and the scope of the disorder is unknown. The disorder is considered rare, but people who have used hallucinogenic drugs often report HPPD symptoms. Psychedelic use has increased over the past several years. According to a 2020 review, the use of LSD increased by more than 56% between 2015 and 2018.
According to the 2020 National Survey on Drug Use and Health, around 2.6% of people age12 years old or older use a hallucinogen. That includes the use of drugs like LSD, PCP, peyote, mescaline, psilocybin mushrooms, MDMA, ketamine, DMT, and Salvia divinorum. That accounts for more than 7 million people.
In 2010, a study found that more than 23% of people who used psychedelics reported constant HPPD symptoms, although very few sought treatment for it.
Which Drugs Can Cause HPPD?
Many drugs have the potential to cause hallucinations and other psychedelic effects. HPPD is commonly associated with LSD, a powerful psychedelic drug known for its intense drug trips and disturbing after-effects. However, other more common drugs like MDMA and even cannabis could cause someone to develop HPPD. Common drugs that could lead to flashbacks include:
- LSD. Lysergic acid diethylamide (LSD) is a potent psychedelic drug that was the subject of intense study through the 20th century. It can cause powerful hallucinations that affect emotions, thoughts, and sensory perceptions. LSD is called acid, and HPPD is often referred to as an acid flashback because of its association with this drug.
- MDMA. 3,4-Methylenedioxymethamphetamine is often used as a club drug because of its ability to increase sociability and empathy. It’s not as potent as other psychedelic drugs in causing hallucinogenic effects, but it is sometimes associated with HPPD symptoms.
- Psilocybin. Psilocybin refers to a psychedelic drug that’s often found in certain types of mushrooms. The drug can cause potent psychedelic effects that can lead to hallucinations and later flashbacks.
- DMT. N,N-Dimethyltryptamine is a naturally occurring chemical compound that can be extracted from plants and used as a potent psychedelic drug. DMT can cause hallucinations and fully altered consciousness. In some cases, DMT experiences can be intense and frightening.
- Mescaline. Mescaline is a cactus that contains a drug called peyote. Peyote is used as a ritual psychedelic and recreational drug, but it can cause hallucinations.
- Cannabis. Marijuana isn’t typically associated with delusions, but high levels of THC can cause hallucinations and symptoms of psychosis. Marijuana can be made with very high levels of THC and low levels of the counteracting DMT, which increases your risk for psychosis.
Hallucinogen-Persisting Perception Disorder Treatment
The human brain is complex, and there is still a lot to learn about HPPD, seizures, migraines, and other neurological issues. HPPD is considered rare, but many former drug users report experiencing symptoms. Still, there is no known cure for the disorder, and there are very few treatment options available. There are no evidence-based treatments or therapies known to be effective in treating HPPD. However, there may be some things you can do to help manage your symptoms.
You can start by speaking to your doctor for more direction. There are medications that could be potentially useful in managing your symptoms, though the research is limited. Some anti-seizure medications could help temper certain HPPD symptoms. You can also speak to a neurologist who may have more insight into how you can manage neurological symptoms. A therapist may help you learn how to cope with symptoms and stressors that can lead to symptoms.
How to Deal with HPPD
HPPD is poorly understood. It’s considered rare, but many people with the disorder have described ways they deal with it daily. Some have also described things they believe trigger HPPD episodes and symptoms. Here are some things to consider if you have hallucinogen-persisting perception disorder.
- Avoid psychoactive substances. Even though hallucinogenic drugs initially cause HPPD, once you have it, it may be triggered by all kinds of psychoactive substances. Some even report symptoms that seem to be triggered by caffeine. Avoiding psychoactive substances beyond any necessary prescriptions could help.
- Wear sunglasses. Symptoms may be caused when you are overwhelmed with bright lights or colors. Sunglasses may help you avoid sudden bright lights that trigger symptoms. This tip is similar to how people with epilepsy and migraines avoid triggers.
- Prepare for visual disruptions. If your symptoms still allow you to drive, make a plan for what you will do if you experience symptoms in a precarious situation.
Learn your triggers. Stress, fatigue, and anxiety might contribute to the emergence of HPPD symptoms. Finding ways to manage these contributing factors may improve your symptoms.