Classic hallucinogens are believed to alter perception by influencing neural pathways in the brain that rely on the neurotransmitter serotonin.
In particular, many of their most notable effects take place in the prefrontal cortex, a region associated with mood, cognition, and perception, as well as in other areas that play a key role in controlling arousal and the body’s physiological reactions to stress and panic.
What Are the Short-Term Effects of Hallucinogens?
Consuming hallucinogenic drugs can lead individuals to perceive images, sounds, and sensations that feel real but are not actually present.
These effects typically begin within 20 to 90 minutes after ingestion and can last up to 12 hours.
The experiences are often unpredictable, influenced by factors such as dosage, the individual’s personality, mood, expectations, and environment.
Hallucinogens like LSD can induce a state similar to drug-induced psychosis, causing distortions in a person’s ability to recognize reality, think logically, or communicate effectively.
Users often describe these experiences as “trips,” with pleasurable and insightful sensations on some occasions.
However, negative experiences, known as “bad trips,” can involve distressing thoughts, overwhelming feelings of anxiety and despair, and fears of losing control, going insane, or dying.
Similar to LSD and psilocybin, DMT exerts its effects by interacting with serotonin (5-HT) receptors in the brain.
Some studies suggest that the human brain naturally produces small amounts of DMT, leading to the hypothesis that endogenous DMT release could play a role in experiences such as alien abduction reports, spontaneous mystical visions, and near-death experiences.
However, this theory remains debated.
Short-term effects of LSD, psilocybin, peyote, DMT, and ayahuasca may include:
1. LSD
- Elevated blood pressure, heart rate, and body temperature
- Dizziness and sleeplessness
- Reduced appetite, dryness in the mouth, and excessive sweating
- Numbness, weakness, and tremors
- Impulsiveness and swift emotional changes that can quickly shift from fear to euphoria, with transitions happening so rapidly that the individual may appear to feel multiple emotions at once
2. Psilocybin
- Feelings of relaxation
- Feelings of nervousness, paranoia, and intense panic responses
- Introspective/spiritual experiences
- Mistaking toxic mushrooms for psilocybin-containing ones can result in accidental and potentially deadly poisoning
3. Peyote
- Elevated body temperature and an accelerated heart rate
- Lack of coordination in body movements (ataxia)
- Excessive perspiration
- Flushing
4. DMT
- Elevated heart rate
- Agitation
- Hallucinations often feature drastically changed environments along with distortions in body perception and spatial awareness
5. Ayahuasca
- Elevated blood pressure
- Intense vomiting caused by the tea
- A deeply transformed state of consciousness with heightened awareness and perceptions of transcendent visions
Short-Term General Effects of Hallucinogens
1. Sensory Effects
- Hallucinations involve experiencing sights, sounds, sensations, or smells in a distorted manner or perceiving things that aren’t actually present.
- Intensified feelings and sensory experiences (brighter colors, sharper sounds)
- Mixed senses (“seeing” sounds or “hearing” colors)
- Changes in the perception of time, such as feeling that time is passing more slowly.
2. Physical Effects
- Enhanced vitality and elevated heart rate.
- Nausea
What Are the Long-Term Effects of Hallucinogens?
LSD users quickly build a high tolerance to the drug’s effects, meaning they need increasingly larger doses to achieve the same experience.
Additionally, using hallucinogenic drugs leads to tolerance for other substances in the same category, such as psilocybin and peyote.
However, classic hallucinogens do not create tolerance for drugs that act on different brain cell receptors.
This means there is no cross-tolerance with substances like marijuana, amphetamines, or PCP, which affect other neurotransmitter systems.
Moreover, tolerance to hallucinogens is temporary—it diminishes after a few days of not using the drug—and long-term users typically do not experience physical withdrawal symptoms when they stop.
The long-term psychological and cognitive effects of peyote remain largely unclear.
One study found no evidence of cognitive or psychological impairments among Native Americans who regularly use peyote in religious ceremonies.
However, these findings may not apply to individuals who abuse the drug recreationally.
Additionally, peyote users may experience hallucinogen persisting perception disorder (HPPD), commonly known as flashbacks.
Furthermore, the active compound in peyote, mescaline, has been linked to fetal abnormalities in at least one report.
The long-term effects of DMT use, as well as its potential for abuse and addiction, remain uncertain. Unlike many other hallucinogens, DMT does not seem to lead to tolerance.
As with certain other hallucinogens, there is limited evidence indicating that ayahuasca use leads to long-term physiological or neurological impairments, particularly among individuals who consume the brew for religious purposes.
In the long term, two potential effects—persistent psychosis and hallucinogen-persisting perception disorder (HPPD)—have been linked to the use of classic hallucinogens (see text box below).
While both conditions are rare, their occurrence is unpredictable and may be more frequent than previously believed.
In some cases, they appear together. Although the exact causes remain unclear, these conditions are more commonly observed in individuals with a history of psychological issues, yet they can still affect anyone, even after just one exposure.
There is no established treatment for HPPD, which involves recurrent and spontaneous flashbacks that, while less intense than the original experience, may persist.
However, antidepressants and antipsychotic medications may help manage mood disturbances and psychotic symptoms.
Additionally, psychotherapy can assist individuals in coping with the fear or confusion associated with visual disturbances and other long-term effects of LSD use.
Ongoing research aims to further understand the causes, prevalence, and long-term impact of these conditions.
Long-Term Effects of Hallucinogens
Persistent psychosis
- Visual disturbances
- Disorganized thinking
- Paranoia
- Mood disturbances
Hallucinogen Persisting Perception Disorder (HPPD)
- Hallucinations
- Other visual disturbances, such as perceiving halos or streaks following moving objects.
- Symptoms sometime misinterpreted as neurological conditions (such as stroke or brain tumor)