What Are the Risks of LSD?

LSD’s effects are unpredictable. They depend on the amount taken, the person’s mood and personality and the surroundings in which the drug is used. It is a roll of the dice whether someone will have a racing, distorted high or a severe, paranoid* low.

Normally, the first effects of LSD start 30 to 90 minutes after taking the drug. Often, the pupils become dilated, body temperature rises or lowers, while blood pressure and heart rate increase. Users might also sweat or feel chills.

Other effects include loss of appetite, sleeplessness, dry mouth and tremors. Users also often experience changes in visual perceptions, becoming fixated on the intensity of certain colors and visual distortions.

Extreme changes in mood can occur, from a spaced-out “bliss” to intense terror. The biggest danger is that LSD users can’t tell what is real and what is caused by the drug. Some LSD users feel an intense false sense of enlightenment. Not only do they dissociate from their usual activities in life, but they also feel the urge to keep taking more of the drug.

Other users suffer severe, terrifying thoughts, loss of control, fear of going insane or fear of death. A bad trip can last up to 12 hours and, once it starts, there is often no stopping it.

* paranoid: extremely and unreasonably suspicious, distrustful or afraid of other people without evidence or justification

Delusion and Hallucinations

Even a moderate dose of LSD can cause intense delusions and visual hallucinations. Users may see objects become distorted, changing shape or size, and experience shifts in sound, color and touch. Sensations might mix together, like hearing colors or seeing sounds. These changes can be frightening and lead the user to panic.

Decision-making and recognition of danger can also become impaired. An LSD user might step out of a window to get a “closer look” at the ground, or stop to admire the sunset, dangerously unaware that they are standing in the middle of a busy intersection.

Many LSD users experience flashbacks, or a recurrence of an LSD trip, often without warning, long after taking LSD.

Bad trips and flashbacks are only some of the risks of LSD use. LSD can also cause long-lasting mental issues like psychosis or severe depression. Unfortunately, some people never recover from acid-induced madness.

Because LSD accumulates in the body, users develop a tolerance for the drug, needing increasingly higher doses to achieve the same effects. This increases the risk of a bad trip and psychosis.

Updated: 2025