LSD (d-lysergic acid diethylamide), also called acid, is one of the most commonly used hallucinogens or psychedelic drugs. It affects a person's perceptions, sensations, thinking, self-awareness, and emotions.
In its pure state, LSD is a white, odorless powder. It's usually sold in liquid form or as tablets or capsules. It's often added to absorbent paper, such as blotter paper, and divided into small decorated squares, with each square being one dose. It's very potent, with small amounts causing strong effects.
The effects, which are unpredictable, usually begin 30 to 90 minutes after taking the drug, are at their strongest 3 to 5 hours later and last for up to 12 hours.
Typical effects include intense sensory experiences (brighter colors, sharper sounds); mixing of the senses (colors are heard or sounds seen); distorted sense of time and space (minutes can seem as long as hours); and distorted body image (a person feels as if he or she is floating or being pulled down by gravity). Physical effects include dilated pupils, raised body temperature, increased heart rate and blood pressure, sweating, loss of appetite, sleeplessness, dry mouth, and tremors.
While using LSD, or "tripping," a person may experience strong feelings of anxiety or fear. The hallucinatory effects can be unpleasant, such as spiders crawling on the skin, or they can be so intense the person feels as though he or she is losing control.
Having a bad psychological reaction to LSD and similar drugs is common. The scary sensations may last a few minutes or several hours and be mildly frightening or terrifying. The user may experience panic, confusion, suspiciousness, anxiety, and feelings of helplessness.
Usually, the negative feelings go away when the drug wears off. Some people experience hallucinations, bizarre behavior, and paranoia for several days afterward. Occasionally, these effects can last weeks or months.
Days, weeks, or even years after using the drug, some people have a repeat experience of the effects, which is called a flashback. The user may see intense colors and other hallucinations. The flashback can seem pleasant or produce severe feelings of anxiety. Flashbacks most often occur in people who used LSD over a long period. But even people who occasionally use LSD may have flashbacks.
Heavy users sometimes develop signs of brain damage, such as impaired memory and attention span.
LSD's effects vary from person to person, depending on many factors, including the person's size, weight, and health, how much of the drug is taken, and whether other drugs are taken with it.
It's dangerous to drive after using LSD because sensory and perceptual distortions may cause the user to "see" things that will cause erratic driving.
If someone has an adverse reaction while using LSD, seek medical attention immediately, then stay with the person until the ambulance arrives.