Psychedelic drugs have become all the rage among scientists. But not for the reasons you might think. From early, rudimentary research of psychedelics in the 1950s and '60s to today’s sophisticated technology, there is a deep interest in understanding how psychedelics affect the brain.
Scientists have been digging for meaningful answers, whether to learn the psychedelic effects on human consciousness or their potential as therapeutics. But what exactly are psychedelics?
What are Psychedelics?
Psychedelic drugs (also known as hallucinogens or hallucinogenic drugs) are a group of psychoactive substances that cause changes in a person’s sensory perception, emotions and thoughts. They can either come in natural or synthetic forms.
Classic Hallucinogens: Short-Term Psychedelic Effects on the Brain
First, consider the classic hallucinogens and their effect on the brain. Psilocybin, lysergic acid diethylamide (LSD), peyote (mescaline) and dimethyltryptamine (DMT) are some of the most common “classic hallucinogens.” These ones typically change the way someone thinks and feels. Consequently, they are also the focus of most research.
Psilocybin is also known as magic mushrooms. It is a natural hallucinogenic component found in mushrooms worldwide, including in the U.S., South America and Mexico.
People who use psilocybin experience paranoia, panic attacks, hallucinations and “spiritual experiences.” Although it may seem contradictory, they also feel relaxed. For users, the latter effect is compared to low doses of marijuana.
Peyote is a cactus with mescaline as its active ingredient and a naturally occurring hallucinogen. The psychedelic effects of mescaline are compared to LSD.
Users of peyote feel their heart rate increase as well as their body temperature. They sweat profusely and experience hallucinations, flushing and ataxia.
DMT is a naturally occurring psychedelic found in certain trees of Central America and the Amazon. DMT is the main component of ayahuasca tea, but people can also use its synthetic form (as a white powder).
DMT users suffer from agitation, elevated heart rate and hallucinations. Also, DMT hallucinogenic “trips” lead to a person seeing distorted bodies and environments.
LSD is a highly hallucinogenic chemical made from acid found in ergot – fungi that spread onto rye grains. In 1938, Albert Hoffman, a Swiss pharmaceutical chemist, initially synthesized it as a stimulant, but didn't know about its psychedelic effects, which he found out a few years later.
LSD users experience numbness, tremors, sweating, loss of appetite, dizziness, impulsiveness, hallucinations that compare to “drug-induced psychosis” and elevated heart rate and blood pressure.
Additionally, there is another group of psychedelics called dissociative drugs. These substances make a person feel as if they are detached from their body or surroundings. This includes hallucinogens such as:
Phencyclidine (PCP) – formerly used as a general anesthetic.
Ketamine – a surgical anesthetic; also known as the infamous “date-rape drug.”
Dextromethorphan (DXM) – used in cold medicine as a cough suppressant.
People consume these psychedelics in many forms, from pills to teas and injections, inhaling or smoking. The short-term effects on the brain, which users tend to call “trips,” vary and can start as early as 15 to 20 minutes and last for about 12 hours.
Long-Term Psychedelic Effects on the Brain
Like the short-term effects, scientists are still searching for more robust data on how psychedelics affect the brain in the long haul. But their research indicates that a few hallucinogenic drugs can cause tolerance (LSD, psilocybin and peyote) and can be addictive (PCP).
Other recognized long-term effects of psychedelics are persistent psychosis and hallucinogen persisting perception disorder (HPPD) – or flashbacks. While a person with persistent psychosis experiences paranoia, visual trouble, mood swings and disorganized thinking, HPPD causes hallucinations, visual problems and symptoms that emulate those of brain tumors and strokes. Experts attribute these conditions mainly to people with a history of mental disorders.
For centuries, psychedelic drugs have had their place in the religious and healing ceremonies of native people in Central and South America. But a strong interest in exploring them as psychotherapeutics (psychedelic therapy) has grown in recent years.
Because the effects of hallucinogens and the symptoms of psychosis intersect, scientists have been studying these substances and ways in which they can shed light on psychiatric disorders such as schizophrenia.
They are also interested in the potential benefits of these substances as effective treatments for other mental illnesses, including severe depression, anxiety, post-traumatic stress disorder and obsessive-compulsive disorder.
The problem is scientists know little about how psychedelics affect the brain – or the exact neurobiological mechanisms. And whatever is known is still up for much debate among the research community.
Studying Psychedelic Effects on the Brain
Several studies have shown that hallucinogens make brain activity more disorderly. Research suggests that psychedelics impact brain connectivity, affect serotonin receptors, create detachment and, of course, cause hallucinations.
For example, in two distinct studies with psilocybin, one using positron emission tomography (PET) and another functional magnetic resonance imaging (fMRI), researchers found that psychedelics alter connectivity areas of the brain, making portions that are usually connected become disconnected. Conversely, the sites that are barely linked then start to liaise.
What’s more, researchers also found that psychedelics, such as psilocybin and LSD, trigger serotonin receptors in the brain – especially serotonin 5-HT2A receptors. This happens mainly in the areas that control cognition and self-awareness (cerebral cortex) and sensory information (visual cortex). When users are hallucinating, some tend to see distorted images or twist their senses, which aligns with scientific research.
Some theories also try to explain the psychedelics' action more specifically, as in a well-known study by Dr. Robin Carhart-Harris and Dr. David Nutt, psychopharmacologists at the Imperial College London.
In this research using fMRI, participants who used psilocybin showed lower brain activity in the “default mode network” – interrelated areas of the brain allegedly in charge of consciousness or sense of self. Yet, the brain image also showed a high level of “ego-disintegration,” or a “spiritual” feeling that comes from the detachment of self.
When you hear psychedelic users talk about their “trips” or mystical experiences, this is what they mean. They experience different sensations that could feel good or unpleasant (“bad trips”).
Carhart-Harris explains, “Within a trip, you can go to heaven and hell.”
Researchers hypothesize the phenomenon as “cognitive flexibility” with altered consciousness – or when the brain is free to operate in a non-conscious or disordered way.
Though these studies have made considerable strides, scientists still don’t know how the brain processes information or communicates changes in areas of the same cognitive process, while under the effects of psychedelics.
For this reason, there is a critical need for more research.