Health Effects of Marijuana and Cannabis Products

Health Effects of Marijuana and Cannabis-Derived Products Presented in New Report – Jan. 12, 2017

In this paper, it’s clear the researchers are desperately trying to reach negative conclusions, even if they must resort to stating only that they “have found limited evidence to suggest that…”.

This sentence wording associates the word “evidence” with the various impairments they then list that may or may not be associated with cannabis, let alone be caused by it.

Nearly 100 Conclusions on the Health Effects of Marijuana and Cannabis-Derived Products Presented in New Report; One of the Most Comprehensive Studies of Recent Research on Health Effects of Recreational and Therapeutic Use of Cannabis and Cannabis-Derived Products

A new report from the National Academies of Sciences, Engineering, and Medicine offers a rigorous review of scientific research published since 1999 about what is known about the health impacts of cannabis and cannabis-derived products – such as marijuana and active chemical compounds known as cannabinoids – ranging from their therapeutic effects to their risks for causing certain cancers, diseases, mental health disorders, and injuries.  

The committee that carried out the study and wrote the report considered more than 10,000 scientific abstracts to reach its nearly 100 conclusions.  

The committee also proposed ways to expand and improve the quality of cannabis research efforts, enhance data collection efforts to support the advancement of research, and address the current barriers to cannabis research

Currently, cannabis is the most popular illicit drug in the United States, in terms of past-month users.  

Based on a recent nationwide survey, 22.2 million Americans ages 12 and older reported using cannabis in the past 30 days.  

This survey also reports that

  • 90 percent of adult cannabis users in the United States said their primary use was recreational, with about
  • 10 percent reporting use solely for medical purposes.  
  • Around 36 percent reported mixed medical and recreational use.

Therapeutic Effects

The committee found evidence to support that patients who were treated with cannabis or cannabinoids were more likely to experience a significant reduction in pain symptoms. 

More likely than what?

For adults with multiple sclerosis-related muscle spasms, there was substantial evidence that short-term use of certain “oral cannabinoids” – man-made, cannabinoid-based medications that are orally ingested – improved their reported symptoms.

Furthermore, in adults with chemotherapy-induced nausea and vomiting, there was conclusive evidence that certain oral cannabinoids were effective in preventing and treating those ailments.

Injury and Death

Evidence suggests that cannabis use prior to driving increases the risk of being involved in a motor vehicle accident.

But there is a mitigating factor: people using cannabis generally drive much less than their alcohol-fueled cohorts.

Furthermore, evidence suggests that in states where cannabis use is legal, there is increased risk of unintentional cannabis overdose injuries among children.

“Poisoning” implies a fatality, but it only means children may get sick from it. But this is only if cannabis is left available to children – it has little to do with the actual effects of the drug.


Regarding the link between marijuana and cancer, the committee found evidence that suggests smoking cannabis does not increase the risk for cancers often associated with tobacco use – such as lung and head and neck cancers.  

The committee also found limited evidence that cannabis use is associated with one sub-type of testicular cancer and insufficient evidence that cannabis use by a mother or father during pregnancy leads to a greater risk of cancers in the children.

Contrary to the reader’s expectations, they mention multiple possible effects of cannabis for which they have either limited or insufficient evidence, but none for which stronger evidence is available.

(Note: This is like me saying “I have found insufficient evidence that pain is relieved by alternative therapies”.  The reader sees the word “evidence” and then sees the phrase “pain is relieved”.  Only those reading carefully will notice that I said “insufficient”, not “sufficient”.)

Heart Attack, Stroke, and Diabetes

more research is needed to determine whether and how cannabis use is associated with heart attack, stroke, and diabetes.

Respiratory Disease

smoking cannabis on a regular basis is associated with more frequent chronic bronchitis episodes and worse respiratory symptoms, such as chronic cough and phlegm production, but quitting cannabis smoking is likely to reduce these conditions.

unclear whether cannabis use is associated with certain respiratory diseases, including chronic obstructive pulmonary disease, asthma, or worsened lung function.

This is because people do not smoke nearly as much cannabis as people smoke tobacco.


There is a lack of data on the effects of cannabis or cannabinoid-based therapeutics on the human immune system.

Nevertheless, limited evidence suggests that regular exposure to cannabis smoke may have anti-inflammatory activity.

Mental Health

evidence reviewed by the committee suggests that cannabis use is likely to increase the risk of developing schizophrenia, other psychoses, and social anxiety disorders, and to a lesser extent depression.

Alternatively, in individuals with schizophrenia and other psychoses, a history of cannabis use may be linked to better performance on learning and memory tasks.

Problem Cannabis Use

There is also evidence to suggest that initiating cannabis use at a younger age increases the likelihood of developing problem cannabis use.

Cannabis Use and the Abuse of Other Substances

the committee found moderate evidence to suggest that there is a link between cannabis use and the development of substance dependence and/or a substance abuse disorder for substances including alcohol, tobacco, and other illicit drugs.

This is a truism because people who smoke cannabis have already decided that using mind-altering substances is desirable, so they will naturally be open to other drugs as well.


The committee found that learning, memory, and attention are impaired after immediate cannabis use.  

This is a truism because such impairments are part of the definition of a mind-altering substance.

Limited evidence suggests that there are impairments in cognitive domains of learning, memory, and attention in individuals who have stopped smoking cannabis.  

This seems to imply that this would not be the case for those that continue using.

In addition, there is limited evidence to suggest that cannabis use is related to impairments in subsequent academic achievement and education as well as social relationships and social roles.  

These convoluted expressions like “limited evidence to suggest” make me furious because they are used to make the reader associate the word “evidence” with the impairments they list.

I could as easily say that “I have found limited evidence to suggest that recovery from addiction causes death.”

(This is actually true because if opioid addicts relapse, their first dose at their previous high dosage with their new lower tolerance will kill them.)

Adolescence and young adulthood are when most youth begin to experiment with substances of abuse, including cannabis, and it is during these periods that the neural layers that underlie the development of cognition are most active.

They don’t mention that this is equally true of every other mind-altering substance. Instead, they make it seem like this is solely the case with cannabis.

The committee also found limited evidence of an association between cannabis use and increased rates of unemployment and low income.

Here they manipulate the reader by using the wording that they “found limited evidence to suggest that” there is an association, which still indicates absolutely nothing about cause and effect.

Of course, there is an association!

But any cause/effect relationship is likely the opposite of what’s implied by sentence wording:

  1. People who are unemployed have more time (and motive) to smoke. 
  2. People with a low income cannot afford fancy travel and recreation so they are much more likely to settle for recreational cannabis at home.

Prenatal, Perinatal, and Neonatal Exposure

Smoking cannabis during pregnancy is linked to lower birth weight in the offspring, some evidence suggests. However, the relationship with other pregnancy and childhood outcomes is unclear.

Challenges and Barriers in Conducting Cannabis Research

For instance, specific regulatory barriers, including the classification of cannabis as a Schedule I substance,impede the advancement of research.

Researchers also often find it difficult to gain access to the quantity, quality, and type of cannabis product necessary to address specific research questions.

I’m disappointed that, despite mounds of evidence against them, the same old tired cliches of “dope-smoking losers” are being supported by all the research papers I see, if not by facts then by convoluted sentence construction that misdirects the reader.

However, I’m learning a lot about how to deliberately mislead readers to guide them into thinking ruts formed by the constant repetition of cultural cliches.


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