Flashbacks Disorder When Taking Acid

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While research suggests that the phenomenon is rare, "acid flashbacks" are more than a memory for some people who have used acid or other hallucinogenic drugs such as phencyclidine (PCP).

While these drug-related hallucinations can be unpleasant and distressing, they are usually temporary. If they do persist, flashbacks can be difficult to cope with and can disrupt a person's everyday life. In some cases, flashbacks can be a sign of an underlying mental health disorder or medical condition. The good news is, these causes can be treated as long as they are properly diagnosed.

What Are Flashbacks?

Flashbacks are a type of disturbed perception or distorted sensory experience that affects your senses; how you see, hear, feel, taste, or smell the things around you.

Unlike memories (which are distant ideas that you know are not happening in the present) flashbacks seem as if they are actually happening in the current moment.

The "realness" of flashbacks from a drug can be so intense that someone may think they must have taken the drug again, or that they are experiencing a mental health crisis (they may fear they are "losing their mind").

Most of the time, someone having a flashback is aware that what is happening at the moment is not real. They know that what they are experiencing is related to a drug they took in the past and that they have not taken the drug again in the present.

If their experience was pleasant, a flashback can cause someone to re-experience the euphoria they got from taking the drug.

However, pleasant flashbacks can also be problematic. For example, someone who is experiencing an amusing flashback in public runs the risk of laughing in a socially inappropriate situation such as a funeral. These experiences can be embarrassing and distressing for the person having the flashback as well as for those around them.

Hallucinogen Persisting Perception Disorder (HPPD)

If someone has flashbacks that cause significant distress or feel uncontrollable, they may have Hallucinogen Persisting Perception Disorder (HPPD). The diagnosis has specific criteria laid out in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

Symptoms of HPPD include:

  • Afterimages
  • False perceptions of movement out of the corner of the eye (peripheral vision)
  • Flashes of color
  • Hallucinations (especially of geometric forms)
  • Halos around objects
  • Inanimate objects appearing alive (for example, walls that appear to be "breathing" or growing)
  • Intensified color
  • Objects appearing larger than they are (macropsia)
  • Objects appearing smaller than they are (micropsia)
  • Trails of images of moving objects

How Long Do Flashbacks Last?

Most of the time, flashbacks related to using drugs only last for a few minutes and do not cause significant distress. The person is fully aware of what's happening and realizes that they are experiencing a hallucination.

Flashbacks can last for minutes, hours, weeks, months, or years.

Flashbacks may occur in episodes, meaning that a person feels normal most of the time and has occasional flashbacks that come on suddenly or unpredictably. Some people find that visual disturbances can even be triggered simply by remembering a time that they took a drug that caused them to hallucinate.

In others, flashbacks can be continuous. A person's distress levels will depend on the nature and content of the hallucinations as well as how they feel about the experience (which is especially influenced by anxiety, depression, or paranoia).

What Are Flashbacks Like?

Some flashbacks are pleasant, like looking up at the sky and seeing the vivid and intense shades of blue, perhaps with some calming, swirly, cloud patterns. However, these visuals can also be highly distressing—for example, imagine how you would feel if you had a fear of spiders and constantly saw them all around you (or even on you).

Other Causes of Flashbacks

People who experience flashbacks may find that the visuals either go away on their own or become easier to control over time as they adjust to the experience.

However, some people find the perceptual disturbances overwhelming and difficult to manage. Flashbacks can have a significant impact on a person's life, such as by making it difficult for them to go to school or work.

In some cases, the visual disturbances that a person assumes are "acid flashbacks" might be a sign of an undiagnosed mental health problem. People who have certain mental health conditions such as substance-induced psychosis, schizophrenia, and post-traumatic stress disorder (PTSD), can also experience flashbacks.

In some cases, flashbacks are caused by an underlying physical condition such as migraines, brain lesions, or a seizure disorder. Specific disturbances in one or more senses (sight, hearing, taste, smell, and touch) can be brought on by eye conditions, neurological diseases, hearing problems, and stroke.

If you are experiencing hallucinations, getting a timely and accurate diagnosis is crucial. While most of the physical and mental health conditions that can cause hallucinations, (including drug use) can be managed or treated, some can have serious consequences if left untreated.

A Word From Verywell

People who experience flashbacks may feel a great deal of distress and even fear that they are losing touch with reality. However, it's important to know that many of the conditions that can cause these visual disturbances—including drug use—are treatable.

If you are experiencing flashbacks, whether or not you have taken LSD or another drug, talk to your doctor. They may refer you to a psychiatrist or an American Board of Addiction Medicine (ABAM) certified physician. These professionals can figure out what is causing your flashbacks, prescribe the appropriate treatment, and make sure you have access to resources, support, and tools to help you cope.

6 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Halpern JH, Lerner AG, Passie T. A Review of Hallucinogen Persisting Perception Disorder (HPPD) and an Exploratory Study of Subjects Claiming Symptoms of HPPDCurr Top Behav Neurosci. 2018;36:333-360. doi:10.1007/7854_2016_457

  3. Lerner AG, Rudinski D, Bor O, Goodman C. Flashbacks and HPPD: A Clinical-oriented Concise ReviewIsr J Psychiatry Relat Sci. 2014;51(4):296-301.

  4. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th edition. Washington, DC; 2013.

  5. Lerner AG, Goodman C, Rudinski D, Lev-Ran S. LSD Flashbacks - The Appearance of New Visual Imagery Not Experienced During Initial Intoxication: Two Case ReportsIsr J Psychiatry Relat Sci. 2014;51(4):307-309.

  6. Krebs TS, Johansen PØ. Psychedelics and Mental Health: A Population Study. PLoS ONE. 2013;8(8):e63972. doi:10.1371/journal.pone.0063972

Additional Reading

By Elizabeth Hartney, BSc, MSc, MA, PhD
Elizabeth Hartney, BSc, MSc, MA, PhD is a psychologist, professor, and Director of the Centre for Health Leadership and Research at Royal Roads University, Canada.