Acid is a slang term for lysergic acid diethylamide (LSD). It belongs to a group of substances called psychedelics. Acid can alter a person’s thoughts, feelings, and the way they perceive the world around them.

When a person uses acid, they can become disconnected from reality. They may see, hear, and sense things that are not real. They may also have strong emotions. This is called a “trip.”

Acid is a powerful mind-altering chemical. Its effects can last up to 12 hours, and a person cannot control when the trip ends.

Some people who have used acid report having a “bad trip,” which means that their experience was unpleasant. A bad trip may be terrifying or deeply disturbing.

The Drug Enforcement Administration (DEA) classifies acid as a Schedule I drug. This means that it has no accepted medical use at this time and has a high potential for misuse.

However, recent studies suggest that LSD may be used as a treatment for mental health conditions such as depression and anxiety.

Below is a chart summarizing the different effects of LSD on the body. Keep reading to learn more about acid and how it works.

short-termlong term
intensified feelings or sensory experiences (brighter lights, stronger sounds); mixed senses (seeing sounds or hearing colors)disorganized thinking
changes in the perception of time (slower or faster)mood disorders
impulsiveness and mood swingsvisual disturbances
loss of appetite, nausea, dry mouth, sweatingpersistent hallucinations
increased heart rate, blood pressure, and temperatureneurological symptoms that may mimic a stroke or a brain tumor
a man holding his head as he is finding out what does acid do to youShare on Pinterest
During an acid comedown, a person may feel very tired and overwhelmed.

The National Institute on Drug Abuse explains that acid and other psychedelics such as DMT change certain neural circuits in the brain. Specifically, they act on the circuits that use the brain’s serotonin levels. Serotonin is a neurotransmitter.

It is serotonin that leads to the perception-altering effects of these hallucinogenic drugs. In fact, acid is one of several serotonergic hallucinogens.

Serotonin helps control a person’s:

  • mood
  • social behavior
  • sleep
  • feelings
  • perceptions
  • hunger
  • body temperature
  • sexual function

Acid primarily affects the prefrontal cortex area of the brain, which controls mood, thinking, reactions, panic, and perception.

As well as from serotonin receptors, acid also binds to dopamine receptors and adrenergic receptors. Dopamine is a neurotransmitter involved in movement and emotion responses, and adrenergic receptors control critical responses to pulmonary, cardiovascular, and metabolic systems.

Learn more about serotonin and dopamine.

When acid disrupts a person’s brain chemistry, they will notice a number of effects. These effects may begin 20–90 minutes after a person takes the drug and can continue for up to 12 hours.

These effects usually include the following:

  • Hallucinations: Hallucinations are things a person sees, hears, feels, smells, or tastes that are not real. Hallucinations from acid can range from exhilarating and exciting to terrifying and traumatic.
  • Mixed senses: A person may feel as though they are “seeing” sounds or “hearing” colors.
  • Severe mood shifts: As a person experiences hallucinations, their mind may react with sudden, intense, and uncontrollable changes in mood. They may become impulsive and shift quickly from euphoria to fear.
  • Slowed or impaired muscle function: A person may lose their coordination or experience numbness, weakness, and shaking. They may also be unable to react to things around them.
  • Lack of concentration and attention: After taking acid, a person may not be able to think clearly, concentrate, remember things, or focus.
  • Sleeplessness: A person who has taken acid will usually be unable to sleep until after the drug wears off.
  • Physical changes: A person may have higher blood pressure levels, a faster heart rate, a higher body temperature, a dry mouth, and sweating.
  • Dizziness: This can cause a person to fall or lose the ability to walk.
  • Loss of appetite: Many people do not eat at all during an acid trip.

A person’s experience with acid is unpredictable. It can vary depending on their mood, personality, surroundings, and several other factors.

A “good trip” may cause feelings of intense pleasure, spiritual or mental clarity, or creativity. However, it can rapidly shift toward a bad trip, causing feelings of terror, paranoia, anxiety, and aggression.

There is no way to “escape” from a bad trip. A person must simply wait for the drug’s effects to wear off.

Many people lose track of time during an acid trip, and until the drug starts to wear off, they may not know how many minutes or hours have passed.

A comedown is the period of time after the initial high of a drug wears off. With acid, the comedown happens after the trip starts to wear off and a person starts to recognize reality again. The comedown may last up to 24 hours or more.

When coming down from acid, a person may feel very tired and overwhelmed due to the variety of emotions and experiences they have just had. They may also be physically exhausted from not having slept for many hours.

An acid comedown may also cause feelings of depression. The person may want to find another source of euphoria and pleasure that matches what they felt with the drug’s effects. Some people may therefore turn to gambling, shopping, or other sources of temporary pleasure.

During a comedown, a person should try to rest and drink non-caffeinated fluids. An acid trip can cause dehydration due to sweating and elevated body temperature, so rehydration is important.

People who use acid can develop tolerance, meaning they will need to use higher doses each time to get the same effects.

However, it is rare for LSD to cause physical dependence. This means someone is experiencing physical withdrawal after stopping or psychological dependence, which means they have developed a substance use disorder.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) defines substance use disorder as the difficulty in controlling substance use despite experiencing negative consequences.

However, some evidence suggests that using acid and other hallucinogens can cause long-term psychosis and hallucinogen persisting perception disorder (HPPD).

HPPD causes visual flashbacks after taking acid. A person may see things that are not real such as “halos” of light, moving objects, or flashes of colors.

A person may also have flashbacks from an acid trip that are upsetting or disturbing, but this is not always the case. These cases are very rare.

When a person experiences HPPD, they will know that the visual disturbances are not real. The disturbances may last for a few seconds or minutes and can even occur months or years after a person uses acid.

In fact, one case documented a woman who had HPPD for 17 years after using acid only once.

Research also suggests that some people may develop schizophrenia after using acid. People who have genetic tendencies toward schizophrenia are more likely to experience this. Again, however, cases are rare.

Several studies have looked at using classical psychedelics for the treatment of mental health conditions that do not respond to traditional treatment methods.

The studies included the use of psilocybin (present in magic mushrooms), ayahuasca, and LSD. The seven studies looked at 130 people with depression, anxiety, or both.

The participants experienced “immediate and significant” antidepressant and anxiolytic effects with the use of psychedelics. These effects lasted for several months.

The common side effects in these studies included headaches, nausea, slightly higher blood pressure levels, a higher heart rate, and transient anxiety.

Although the results sound promising, researchers must continue to investigate these preliminary findings. The Food and Drug Administration (FDA) has not approved acid for these uses.

It is also important to note that LSD is illegal in the United States.

The following are some answers to common questions about acid.

How is LSD classified?

According to the Controlled Substances Act, the U.S. government classifies LSD as a Schedule I substance. Drugs classified this way have a high potential to cause harm.

Does LSD show up in a drug test?

Regular urine tests cannot detect LSD. Research shows that 200 micrograms (mcg) of LSD may stay in a person’s blood for approximately 12 hours. There is not enough research to say definitively how long LSD may be detected in a person’s hair follicles.

Acid has powerful effects on a person’s mind. Most of the time, these effects are temporary and will not cause long-term damage. However, some people may have ongoing flashbacks or trauma that can cause fear or feelings of depression.

Although studies are at an early stage, there is some evidence to suggest that LSD may be effective in treating certain mental health conditions, but researchers must continue to explore this. At present, there is no FDA approval for this use, and the drug remains illegal in the U.S.

If a person is facing substance use challenges or experiencing mental health issues, they can contact the Substance Abuse and Mental Health Services Administration National Helpline at 1-800-662-HELP (4357).