DRCNet Response to the
Drug Enforcement Administration
LSD in the United States

LSD Use and Effects


LSD is ingested orally. A microdot tablet or square of the perforated LSD paper is placed in the user’s mouth, chewed or swallowed, and the chemical is absorbed from the individual’s gastrointestinal system. Paper squares are the preferred medium because their small size makes them easy to conceal and ingest. Also, because LSD is not injected or smoked, paraphernalia are not required.

The National Household Survey on Drug Abuse data for LSD are limited to estimates of lifetime use, defined as the use of LSD at least once in a person’s lifetime. During 1993, 13.2 million Americans, 12 years of age and older, reported having used LSD at least once compared to 8.1 million in 1985, an increase of more than 60 percent. In addition to the steady increase in LSD use since 1990, the data reveal two significant expansions in the number of lifetime users of LSD; one expansion occurred from 1985 to 1988 and the other from 1990 to 1991.

According to the 1994 Monitoring the Future Study, lifetime, past-year, and past-month use of LSD among seniors in the class of 1994 increased to the highest level since at least 1985. Moreover, the survey revealed that LSD use has increased in every category (except daily use) at every grade level. In addition, the proportions of students associating great risk with the use of LSD and other drugs have been declining significantly.

The Drug Abuse Warning Network (DAWN) indicates that the number of LSD-related hospital emergencies remains low compared to those related to cocaine, heroin, marijuana, methamphetamine, phencyclidine, and other major illicit drugs of abuse. For example, over the past 5 years, the number of LSD-related hospital emergencies has not exceeded 3,900 in any given year while the number of cocaine-related hospital emergencies has approached 125,000 per year during that same time frame. The low number of LSD-related hospital emergencies most likely is due to the fewer adverse reactions generated by the low-potency LSD that has been produced since the late 1970’s. As a result, the DAWN figures do not reflect the increases in LSD use measured by other indicators such as the National Household Survey on Drug Abuse and the Monitoring the Future Survey.

DAWN data also reveal that the majority of LSD abusers are in their late teens and early twenties and usually are white males. This general profile of LSD users has been a common characteristic associated with the drug since it became popular as a substance of abuse and, for the most part, has been unchanged since at least 1989. In 1993, LSD-related emergency room episodes ranked fourth among youths aged 6 to 19, after alcohol in combination with other drugs, marijuana, and cocaine.


LSD generates a wide variety of effects, the intensity of which are related to the size of the dose ingested, the mental state of the user, and the setting in which it is used. Although the minimum dose required to induce effects is considered to be 25 micrograms, a dose of as little as 10 micrograms can relax inhibitions and produce mild euphoria.14 As the dosage is increased, the effects become more pronounced and more prolonged. The LSD high is uncontrollable once the drug has been ingested because there is no antidote.15

LSD is absorbed easily from the gastrointestinal tract, and rapidly reaches a high concentration in the blood. It is circulated throughout the body and, subsequently, to the brain. LSD is metabolized in the liver and is excreted in the urine in about 24 hours.

Several factors provide LSD with a virtually inherent governor to its regular use, meaning that the drug will never become as frequently abused as other drugs, most notably, crack cocaine. First, the duration of the effects, which may persist for up to 12 hours or more, ensures that the user will not need to purchase the drug on a rapidly recurring basis. Second, tolerance to the drug develops rapidly if used daily, rendering its repeated ingestion useless, and cannot be overcome by ingestion of increased dosages.16 Third, the uncertain and mixed effects, especially adverse reactions, lead to erratic instances of LSD use. Finally, the extremely powerful and intense hallucinations often prompt users to abstain from LSD ingestion as they require periods of reorientation.

Physical Effects

LSD use can produce a number of physical changes: mydriasis (prolonged dilation of the pupil of the eye), raised body temperature, rapid heartbeat, elevated blood pressure, increased blood sugar, salivation, tingling in fingers and toes, weakness, tremors, palpitations, facial flushing, chills, gooseflesh, profuse perspiration, nausea, dizziness, inappropriate speech, blurred vision, and intense anxiety.17 Death caused by the direct effect of LSD on the body is virtually impossible. However, death related to LSD abuse has occurred as a result of the panic reactions, hallucinations, delusions, and paranoia experienced by users.

LSD distorts electrical messages sent to and from various parts of the brain, primarily those pertaining to visual information. Messages from any of the senses can be perceived as merged together, creating a sensation known as “synesthesia.” This most commonly is represented as “hearing colors” or “seeing sounds.”

LSD also affects moods and emotions and suppresses memory centers and other higher cerebral functions, such as judgment, reason, behavior control, and self-awareness.18 The combination and intensity of these factors create the profound mental effects most closely associated with LSD.

Mental Effects

The mental effects most commonly associated with LSD use, particularly at high doses, are visual images or hallucinations, often involving simulated philosophical or religious connotations. It is this artificial imagery which has been advocated erroneously as providing true psychological insight and benefit.

The cause of most LSD-related problems is the intense visual illusions triggered that seem real and become overpowering, prompting the user to want to withdraw from the drug state immediately.19 Initially, at lower dosage levels, the visual images are intensified in color or flashes of light are seen. The visual images progress to brightly colored geometric designs and become distorted. At higher dosages, images appear as distortions of reality or as completely new visual images and can be seen with the eyes open or closed.

Hallucinations also take other forms: thoughts become dreamlike or free-flowing, perception of time can become slowed or distorted, and out-of-body experiences may occur or the perception that one’s body has merged with another person or object.20

Emotional responses to the vivid hallucinations can be wide-ranging, from euphoria and contentment to disturbing feelings of confusion, fear, and despair. Moods can change profoundly in a short period of time, from excitability to tranquility.21

The consequences of LSD use can be deleterious, not merely benign as is commonly perceived. Powerful hallucinations can lead to acute panic reactions when the mental effects cannot be controlled and when the user wishes to end the drug-induced state. While these panic reactions more often than not are resolved successfully over time, prolonged anxiety and psychotic reactions have been reported.22 The mental effects can cause psychotic crises and compound existing psychiatric problems.23


Flashbacks are one of the most dangerous side effects of LSD use. They are recurrences of images or effects that were experienced during a previous LSD administration and they can vary in frequency and duration. Flashbacks can occur spontaneously or they can be spurred by the use of other drugs (particularly marijuana or hashish), emotional stress, fatigue, or movement from a light to a dark environment. These flashbacks can last from a few seconds to several hours. Ironically, some experienced LSD users do not consider flashbacks to be an adverse consequence of LSD use and actually enjoy the renewed perceptions or images as a “free trip.”24


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