Cannabis and the Brain

by M.P. Pellicer | Stranger Than Fiction Stories
Doctors are mystified when they have patients complaining of nausea and vomiting more than 20 times in one day, and dropping weight to a life-threatening level. This is a condition that they are seeing more frequently in chronic, heavy pot users.

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Areas of the brain affected by cannabinoids

​Desiree Haight, 46, came to the hospital after vomiting more than 30 times per day. She was hospitalized for months and was fed with a tube; she had dropped to less than 100 pounds. She was a long-time pot smoker when she started to experience abdominal cramps, nausea and vomiting that left her incapacitated. 

Initially the doctors were mystified and then thought it was psychosomatic. Thirteen years passed where she had a recurrence of these symptoms, and in 2018 a doctor asked her the right question: "was she taking hot showers to relieve her symptoms?" The answer was yes, which dovetailed with findings of physicians in both Canada and the United States that these symptoms are more prevalent with the increased legalization of recreational marijuana.

The hot showers actually dehydrates the person more making them sicker, and possibly leading to a type of renal failure. "It causes frequent visits to the emergency department," according to Dr. Timothy Meyers, medical director of emergency services for Boulder Community Health. "People feel terrible when it happens."

Physicians don't totally understand the mechanism that produces these symptoms, but suspect ease of availability, and stronger strains can be contributing factors. "It’s a very unique clinical syndrome that is characterized by a number of unique presentations," Dr. Eddie Lang said, adding that one of them is a distinctive guttural sound not apparent in other types of vomiting. Identifying the source of what is making the patient feel so sick, is half the battle as doctors find that these patients are resistant to their instruction, which is to stop smoking pot for an indefinite period of time. 

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Cases of cannabinoid hyperemesis syndrome (CHS) have doubled since 2017

Cases of cannabinoid hyperemesis syndrome (CHS) have doubled since 2017. In a worse case scenario it causes extreme dehydration, seizure and kidney failure.

In June, 2024 a study described where a 22-year-old woman died from heart problems, which doctors blamed on CHS due to 8 years of regular cannabis use. Prior to her death she had been to the doctor 6 times presenting with the symptoms of CHS.

According to Dr. Maria Isabel Angulo with the University of Illinois, CHS affects an estimated 2.75 million Americans each year. Men between the ages of 16 and 34 has seen the most increase. She attributes this to the potency of THC in marijuana currently on the market, and availability due to the legalization.

CHS is typically divided into three phases:

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• Prodromal phase: Marked by waves of nausea in the morning and abdominal discomfort (but no vomiting), this phase may last for months or even years.
• Hyperemetic phase: Marked by intense and persistent nausea, vomiting, abdominal pain, dehydration, and weight loss.
• Recovery phase: After abstaining from cannabis, symptoms typically improve within days and resolve within weeks.

More potent marijuana is believed to be a contributing factor to CHS

Recent research has found that genetic factors contribute to CHS. These genes affect dopamine activity, pain responses, mood regulation and gut disturbances. The genes are the following: COMT gene, TRPV1 gene, CYP2C9 gene, DRD2 gene and ABCA1 gene. This findings indicate there is a complex genetic basis for CHS.

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Plenty of regular, long-term, and high-potency users of cannabis do not report CHS symptoms. However, it may take years for CHS to develop. Most cases of CHS have been shown to occur in people who consume cannabis roughly 20 days per month, and about 75% of those patients have used cannabis regularly for more than a year. More than 70% of CHS sufferers are men.

It found that people with schizophrenia are also more likely to use cannabis.

Cannabis Use and Schizophrenia
A new scientific study has linked smoking cannabis with certain psychiatric conditions such as schizophrenia. It found that people with schizophrenia are also more likely to use cannabis. The researchers used  a analysis technique called "Mendelian randomization".

The study identified 35 different genes associated with cannabis use with the strongest associations in a gene called CADM2, which is associated with "risky behavior, personality and alcohol use,” said professor Jacqueline Vink, the study’s lead author.

One of the largest correlations was the genetic overlap between cannabis use and the risk of schizophrenia. People with schizophrenia use cannabis as a form of self-medication, however there might be a reverse cause-and-effect relationship, in which cannabis use could contribute to the risk of schizophrenia.

Also found was a genetic overlap between cannabis use and the use of tobacco and alcohol. Personality types that are prone to more risky behavior or were more extraverted also had a similar overlap for the use of cannabis. 

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A convergence of evidence shows that use of Cannabis sativa is associated with increased risk of developing psychotic disorders, including schizophrenia, and earlier age at which psychotic symptoms first manifest. Cannabis exposure during adolescence is most strongly associated with the onset of psychosis amongst those who are particularly vulnerable, such as those who have been exposed to child abuse and those with family histories of schizophrenia. 

Cannabinoid Guide

Schizophrenia is a brain disease that affects approximately 1% of the population. Symptoms are: "delusions, hallucinations, disorganized thinking, social withdrawal, amotivation, affective flattening, deficits memory, executive functioning, processing speed, and a decline in social and occupational functioning".

In 1987, it was reported that heavy cannabis use was associated with a 6-fold increase in risk for schizophrenia, based on a 15-year follow-up of Swedish military conscripts.

Another study found that patients with schizophrenia who used cannabis versus those that don't have a higher rate of psychosis in their family histories.

Two large, longitudinal studies confirmed that a history of childhood maltreatment and cannabis use (prior to a diagnosis of schizophrenia) are associated with a higher risk of psychosis. An urban environment is associated with psychosis and cannabis use.

It has also been found that those who develop schizophrenia after cannabis used tend to have more severe psychotic symptoms.

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The evidence for an association between cannabis use and schizophrenia is compelling, as is the evidence that THC and synthetic cannabinoids can provoke symptoms of schizophrenia in healthy subjects and exacerbate symptoms in patients with schizophrenia. THC has multiple actions that could disrupt brain development in vulnerable adolescents, including impairment of neuroplasticity, dysregulation of dopamine and glutamate signaling, and, possibly, neurotoxicity.