LSD is a potent drug. It causes hallucinations and has very unpredictable effects. It is manufactured from lysergic acid, which is found in a fungus that grows on rye and other grains.

LSD can have long-lasting impacts on a person's brain and emotional state. This is true even if someone uses the drug only once.

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About LSD

LSD (also known as acid, mellow yellow, California sunshine, window pane, blotter and dots) stands for lysergic acid diethylamide. In its pure form, LSD is a white, odourless and slightly bitter crystalline powder.

On the street, it is often sold as small squares of LSD-soaked blotting (absorbent) paper. These squares each contain 1 dose of LSD and are taken by mouth, generally held on the tongue or swallowed.

LSD can also be sold as a powder or as capsules and tablets. The powder may be made into miniature powder pellets called microdots, which are taken by mouth.

LSD crystals may also be dissolved into liquid. This liquid can be sold in small breath freshener droppers or applied to various substances, including:

  • sugar cubes
  • gelatin squares
  • gum
  • candy
  • cookies
  • postage stamps

Rarely do people try inhaling or injecting LSD.

The drug's effects are felt gradually within 30 to 60 minutes after consumption and peak in 2 to 4 hours. Afterwards, the effects fade over a period of 10 to 12 hours. People refer to their experience under the influence of LSD as a "trip".

LSD produces vivid visual effects called pseudo-hallucinations because users are aware that they are not real. Whether or not a person experiences hallucinations while using LSD is related to the dose consumed. It may also be affected by the person's mood, thoughts and surroundings.

Taking LSD can be an unpredictable experience. People can react very differently to it, even in the same trip. Reactions may range from pleasant sensations of well-being, joy and wonder to uncomfortable and very frightening feelings.

People may even experience a psychotic episode. These reactions are often described as either a good or bad trip. There is no guarantee that the same experience will happen again after using LSD.

Short-term effects of LSD

LSD use can lead to short-term mental and physical effects.

Mental effects

LSD causes hallucinations and affects people's brains by:

  • changing their senses, moods and thoughts
  • distorting their perceptions of themselves and of the world around them
  • altering what they hear, taste, feel and smell (brighter colours, sharper sounds)
  • mixing up their senses, so that they hear colours and see sounds
  • making them see, hear or feel things that are not really there

Other effects of LSD can include:

  • feelings of weightlessness or heaviness
  • feeling disconnected from your body
  • impaired judgment of distance, time or speed
  • altered or impaired memory
  • difficulty concentrating
  • extreme changes in mood, from:
    • joy to desperation
    • calmness to anxiety or depression
    • well-being to terror or aggression

Deaths associated with LSD use are usually the result of accidents caused when a person senses or sees something abnormally. This can lead to errors in judgment. For example, users may be convinced that they can fly or can walk through traffic unharmed.

Physical effects

Some of the effects reported by users during and after the time that LSD is taken include:

  • increased blood pressure and heart rate
  • increased body temperature or sweating
  • dizziness
  • sleeplessness
  • numbness or tremors
  • dilated pupils
  • loss of appetite, nausea or dry mouth
  • decreased coordination and weakness

Long-term effects of LSD

The health risks related to frequent LSD use are more mental than physical. The drug can have long-lasting effects on a person's brain and emotional state. Sometimes the effects, such as depression, flashbacks, psychosis and paranoia, continue for years after LSD use.

However, if women use LSD during their pregnancy, there may be an increased risk of:

  • spontaneous abortion
  • birth defects in the infant


A long-term result of LSD use is flashbacks (known as hallucinogen persisting perception disorder). This is the spontaneous and unpredictable re-occurrence of visual distortions or emotional experiences from a previous episode of LSD use. Frequent users of LSD are at greater risk of experiencing flashbacks. However, flashbacks can occur after only a single use.

Not everyone who takes LSD experiences flashbacks. When people do have them, they may occur over and over. While flashbacks usually decrease over time, they can continue for years. There is currently no established treatment for this disorder.


Another condition that can develop long after a person has stopped LSD use is persistent psychosis. Psychosis refers to losing contact with reality. Common symptoms include:

  • changes in thinking patterns (disconnected thoughts)
  • delusions
  • false beliefs that have no basis in fact
  • hallucinations
  • changes in mood
  • disorganized behaviour

This can happen to people who do not have any history or symptoms of psychological disorders. This condition may last for months or years.

Addiction and withdrawal

People who use LSD regularly may become tolerant to its effects. This means they need to take more and more of the drug to experience the same effects.

Tolerance to LSD can develop very quickly. If a person keeps using LSD for several days, no amount of the drug will produce an effect. Sensitivity to the drug's effects only returns if it is not used for 3 to 4 days.

LSD does not cause physical dependence. Unlike with some other drugs, frequent users are not driven to use it. Even though they do not experience physical withdrawal symptoms, some people can develop a psychological dependence on the drug.

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