Drugs and Substances: Learn It 5—Hallucinogens

Hallucinogens

hallucinogens

Hallucinogens are a diverse class of drugs that induce significant changes in sensory perception and cognitive experiences. These alterations can manifest as visual or auditory hallucinations, distorted body sensations, and a skewed sense of time. Some well-known hallucinogens include psilocybin (commonly known as “shrooms”), mescaline (found in peyote), and LSD (lysergic acid diethylamide). These are sometimes called psychedelic or dissociative drugs.

Different hallucinogens interact with various neurotransmitter systems in the brain. For instance, mescaline and LSD primarily act as serotonin agonists, enhancing the activity of serotonin in the brain. On the other hand, substances like PCP (angel dust) and ketamine act as antagonists of the NMDA glutamate receptor. Generally, hallucinogens are not considered as addictive as other drug classes like stimulants or opioids.

An illustration shows a colorful spiral pattern.
Figure 1. Psychedelic images like this are often associated with hallucinogenic compounds. (credit: modification of work by “new 1lluminati”/Flickr)

Cannabis, also known as marijuana, is often grouped with hallucinogens, but it’s essential to note that its effects are more varied and can include features of stimulants and depressants. The active compound in marijuana, THC (tetrahydrocannabinol), interacts with the endocannabinoid system in the brain, affecting mood, perception, and appetite.

Understanding Marijuana

Marijuana has various mental and physical effects, which include euphoria, relaxation, altered states of mind and sense of time, difficulty concentrating, impaired short-term memory, impaired body movement (balance and fine psychomotor control), and an increase in appetite. The onset of effects is felt within minutes when smoked, but may take up to 90 minutes when eaten. The effects usually last for two to six hours, depending on the amount used. Physical effects may include dry mouth, red eyes, increased heart rate, difficulty breathing, or nausea. At high doses, mental effects can include anxiety, delusions (including ideas of reference), hallucinations, panic, paranoia, and psychosis.

While many argue that marijuana is not as harmful as other commonly abused drugs, it is still a mind-altering substance that comes with risk. Though it is not as addictive as nicotine, 30% percent of marijuana users are likely to develop a dependency on the drug.[1] There is also a strong relation between cannabis use and the risk of psychosis, though the direction of causality is debated. Other long-term adverse effects may include decreased mental ability in those who started regular use as adolescents, chronic coughing, susceptibility to respiratory infections, and cannabinoid hyperemesis syndrome.

Medical Marijuana

As of 2023, medical marijuana is legal in a majority of U.S. states, and its recreational use is also legal in several states. Medical marijuana is prescribed for various health conditions, such as stimulating appetite in chemotherapy patients and managing chronic pain or muscle spasms. However, federal laws still classify marijuana as an illicit substance, complicating research efforts to understand its full range of medicinal benefits.

Medical marijuana is marijuana that is prescribed by a doctor for the treatment of a health condition. For example, people who undergo chemotherapy will often be prescribed marijuana to stimulate their appetites and prevent excessive weight loss resulting from the side effects of chemotherapy treatment. Marijuana also shows some promise in the treatment of a variety of other medical conditions (Mather, Rauwendaal, Moxham-Hall, & Wodak, 2013; Robson, 2014; Schicho & Storr, 2014).

A photograph shows a window with a neon sign. The sign includes the word “medical” above the shape of a marijuana leaf.
Figure 2. Medical marijuana shops are becoming more and more common in the United States. (credit: Laurie Avocado)

There is quite a bit of controversy within the scientific community as to the extent to which marijuana might have medicinal benefits due to a lack of large-scale, controlled research (Bostwick, 2012). As a result, many scientists have urged the federal government to allow for the relaxation of current marijuana laws and classifications in order to facilitate a more widespread study of the drug’s effects (Aggarwal et al., 2009; Bostwick, 2012; Kogan & Mechoulam, 2007).

Until not too long ago, the United States Department of Justice routinely arrested people involved with the use of marijuana in medicinal settings. In the latter part of 2013, the United States Department of Justice issued statements indicating that they would not continue to challenge state medical marijuana laws. This shift in policy was likely a response to recommendations by the scientific community and also a reflection of changing public opinion regarding marijuana.

Summary of Psychoactive Drugs

Substance use disorder is defined in DSM-5 as a compulsive pattern of drug use that persists in spite of negative consequences. Both physical and psychological dependence are often involved with this disorder. Alcohol, barbiturates, and benzodiazepines are central nervous system depressants that affect GABA neurotransmission. Cocaine, amphetamine, cathinones, and MDMA are all central nervous stimulants that agonize dopamine neurotransmission, while nicotine and caffeine affect acetylcholine and adenosine, respectively. Opiate drugs serve as powerful analgesics through their effects on the endogenous opioid neurotransmitter system, and hallucinogenic drugs cause pronounced changes in sensory and perceptual experiences and vary with regards to the specific neurotransmitter systems they affect.

Visit the Mouse Party website to see a visual example of how drugs alter the chemicals in the brain.
  1. NIDA. 2021, April 13. Is marijuana addictive? Retrieved from https://nida.nih.gov/publications/research-reports/marijuana/marijuana-addictive on 2023, October 17 ↵