What Are The Neurological Effects Of Cannabinoids?
THC, CBD, and other cannabinoids found in marijuana have the ability to bind to the human body’s natural endocannabinoid system. This neural system plays a role in sleep, pain management, immune system responses, appetite, brain activity, and more. Cannabis connects to this system by binding with CB1and CB2 receptors.
While CB2 receptors are found throughout the body, CB1 receptors are concentrated in the brain. THC has a high affinity for CB1 receptors. When THC activates these receptors, they can cause alterations in the ways the brain processes sights and sounds.
What Is A Hallucination?
“While you are high, you may experience altered senses, such as seeing brighter colors.” This explanation from the National Library of Medicine describes a phenomenon that’s familiar to most cannabis users. These well-known visual enhancements likely inspired jazz legend and lifelong cannabis advocate, Louis Armstrong, to croon about “the colors of the rainbow” in his famous rendition of Wonderful World.
But seeing “skies of blue and red roses, too” is not the same as a hallucination. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines hallucinations as:
Perception-like experiences that occur without an external stimulus. They are vivid and clear, with the full force and impact of normal perceptions, and not under voluntary control.
The National Library of Medicine adds:
Hallucinations involve sensing things such as visions, sounds, or smells that seem real but are not. These things are created by the mind.
Can Cannabis Cause Hallucinations?
Based on the definitions given above, the typical visual affectations common to marijuana use would not classify as hallucinations. They are enhancements and alterations to what is real, while a true hallucination creates a false reality.
So most marijuana users aren’t hallucinating. But, in rare cases, it does happen.
A case study published in Cannabis and Cannabinoid Research documented the case of a 30-year-old man who experienced both visual and auditory hallucinations after vaping marijuana with 25mg THC content. Vaping was done in a laboratory setting, and evaluations of the subjects’ mental state were made with the Hallucinogen Rating Scale (HRS). The HRS is a widely-used self-report questionnaire that is used to evaluate the acute effects of hallucinogenic drugs.
Test results showed the volunteer was experiencing hallucinogenic effects at the same or higher levels that would be expected from psychedelic drugs such as psilocybin. The authors noted, however, that the nature of the hallucinatory experience was not identical to known psychedelics, writing:
The hallucinatory experience in this case was qualitatively different than that typically experienced by participants receiving classic and atypical hallucinogens, suggesting that the hallucinatory effects of cannabis may have a unique pharmacological mechanism of action.
In contrast to marijuana, which influences CB1 and CB2 receptors, psychedelic agents such as LSD and psilocybin access a different neural pathway to create hallucinatory effects. These compounds target serotonin receptors known as 5-HT2A. Research published by the Journal of Neuroscience shows that the activation of these receptors creates auditory and visual hallucinations.
The Journal of Psychopharmacology indicates that, under certain circumstances, marijuana may mimic the effects of known hallucinogens. Based on self-reported effects from study participants, the authors concluded:
High doses of cannabis can create subjective effects comparable to those identified in trials of psilocybin.
High-Strength THC Can Create Psychedelic Experiences
There are indications that the relationship between cannabis use and hallucinatory experiences has changed due to the increased consumption of high-THC cannabis. Writing for the Yale School of Medicine, author Isabella Backman quotes Yale Professor of Psychiatry, Deepak Cyril D’Souza, MD, as stating:
In 1995, the average THC content in cannabis seized by the Drug Enforcement Administration was about 4%. By 2017, it had risen to 17% and continues to increase. Beyond the plant, a staggering array of other cannabis products with an even higher THC content like dabs, oils, and edibles are readily available – some as high as 90%. “The marijuana and cannabis products that your grandparents may have used are very different from what’s out there now.”
A pivotal study in the understanding of high-THC’s hallucinatory potential appeared in the April 2018 issue of Neuropsychopharmacology. Based on laboratory results, a team of researchers determined that chronic exposure to THC stimulated the same 5-HT2A receptors targeted by hallucinatory drugs.
They concluded:
The present study demonstrates that chronic THC exposure leads to the over-activation of a pro-hallucinogenic signaling pathway of 5-HT2AR. [These] findings describe, for the first time, the molecular mechanisms underlying the link between cannabis abuse and susceptibility to schizophrenia-like symptoms.
The most recent insights on this effect were noted in a 2024 review of literature on the psychedelic effects of cannabis. Based on available research information, the authors wrote:
The evidence suggests that high-THC cannabis may be able to elicit psychedelic effects, but that these effects may not have been observed in recent controlled research studies due to the doses, set, and settings commonly used.
What Is Greening Out?
The trend toward high-THC cannabis and edible products corresponds with an increase in reported cases of marijuana toxicity. A survey of records from 2006 to 2018 published in Drug and Alcohol Dependence shows an upward trend in cannabis-related emergency room visits. More recent data is not currently available. Based on information from the Oregon Health Authority a majority of reported cases are related to unintentional ingestion of edibles by children, underestimation of the effects of edibles, or the result of a long-term cannabis disorder.
Also on the rise is a less well-described reaction to cannabis commonly known as “greening out.” Medical literature does not provide a specific description of this phenomenon. It is difficult to quantify the frequency of these events, as most cases are self-resolved and do not lead to medical interventions that create searchable records. Because of this, most information on the subject comes from websites of various rehabilitation and drug intervention organizations and social media discussions.
In 2018 the the Urban Dictionary added the term to their online document, with the explanation:
Greening out basically is when you smoke and get really sick. Normally it comes with dizziness, impaired vision and balance, passing out, nausea, or in some extreme cases vomiting. You may also become sober extremely quickly. Sometimes you may also experience chills and cold sweats. Normally, in most cases, it happens with non-smokers who are doing it for the first time.
A blog entry from the Summit Wellness Group provides a similar description:
Greening out takes place when someone has smoked or consumed too much marijuana for their body to handle. This occurs most frequently when edibles are consumed. It can also happen to someone when they smoke for the first time and do not know their body’s tolerance. Greening out may also happen when a person drinks alcohol before smoking, and the combination of weed and marijuana causes their body to react negatively.
Common symptoms of greening out described by the Washburn House rehabilitation center include:
- Nausea and vomiting
- Dizziness, confusion and blurred vision
- Paranoia, anxiety and mild hallucinations
- Pale skin or sweating
- A rapid heart rate
How To Fix Greening Out
In the absence of medical research on the subject of greening out, most advice on dealing with and resolving these episodes comes from rehabilitation websites. Based on advice common to a number of these sites, concerned patients would do well to remember:
- Don’t panic: While the debilitation of a green-out can be frightening, they are not fatal.
- Take deep breaths: A focus on deep breathing can help you maintain a sense of calm and control
- Hydrate: Drinking water will help mitigate the effects of cannabis, while juices will restore blood sugar levels and may reduce symptoms of lightheadedness.
- Rest: Relaxation, lying down, and sleep give the body and mind time to process the effects of a cannabis overdose.
- Eat: Fats should be avoided, while foods high in carbohydrates may help metabolize cannabis.
Green-outs may resolve themselves in minutes or they may last for hours. Most sources indicate that a green-out rarely lasts for more than a day. If symptoms do persist, medical intervention may be required.
Is Greening Out The Same As CHS?
Greening out can be caused by a single session of marijuana over-consumption. It can affect anyone from first-time users to regular consumers. The disorder known as cannabinoid hyperemesis syndrome (CHS) is an affliction that may develop over a long period of chronic marijuana use.
The American College of Gastroenterology writes:
CHS usually starts after years of using marijuana many times a week. Initial symptoms are feeling sick to the stomach, belly pain and the feeling like you may throw up. A lot of people can still eat without throwing up. After about 10-12 years of chronic marijuana use, patients begin to have a strong feeling of sickness, throwing up, and belly pain. This is normally when people go see a doctor to find out what is causing these problems. They start to feel better when they stop using marijuana but can feel bad if they use it again.
According to the Cedars-Sinai, treatments for CHS can involve:
- Ceasing all marijuana use
- Frequent hot showers
- Intravenous (IV) fluid replacement for dehydration
- Medicines to help decrease vomiting
- Pain medicine
- Proton-pump inhibitors, to treat stomach inflammation
- Prescribed medicines for relaxation (benzodiazepines)
Following cessation of cannabis use, symptoms typically ease with one to two days.
What Are The Symptoms Of Cannabis Withdrawal?
While medical and research communities remain divided on the subject of marijuana addiction, evidence shows that some habitual and long-term users experience cannabis withdrawal symptoms (CWS) when they stop consuming marijuana products. Research published in the Substance Abuse Rehabilitation reported that between one and two-thirds of patients seeking outpatient treatment for cannabis detoxification developed CWS symptoms. These effects were noted as typically being mild to moderate in severity.
The January 2022 edition of the Addiction provides insights into the symptoms and management of CWS, with the authors writing:
- CWS symptoms usually begin within 24-48 hours after cessation of use
- Most symptoms generally peak on days 2-6
- Some symptoms may last up to 3 weeks or more for heavy users
The researchers go on to note that the most common features of cannabis withdrawal are:
- Anxiety
- Irritability
- Anger or aggression
- Disturbed sleep/dreaming
- Depressed mood
- Loss of appetite
Less common physical symptoms include chills, headaches, physical tension, sweating, and stomach pain. The report states that there are no medications currently approved specifically for medically assisted CWS treatment, while noting that some individuals may benefit from supportive counseling.
Do You Have Questions About Medical Marijuana?
CannaMD is actively engaged in ongoing medical marijuana research and maintains a network of state-licensed physicians who certify patients to receive medical marijuana treatment. If you are interested in learning more about cannabis therapies, please contact our offices at (855) 420-9170.
