The 1964 sixth grade class filed up the stairs to their classroom.
In a momentary pause at the landing to allow the crowd to dissipate a young male voice is heard,
“Wanna marijuana?”
His friend asks, “What is that?”
He smartly replies,
The “It’s a cigarette that makes you feel funny.”
Marijuana was anything but a household word in the early 1960s. By mid- to late decade a number of interchangeable names for the vegetation emerged into the hippie, if- it- feels- good- do it social scene; weed, pot, THC, or cannabis.
Cannabis, an ancient plant, cultivated throughout the world both for its recreational and medicinal purposes has made people “feel funny” for thousands of years, which means the sixth grader had it right—on some counts. He probably had no idea that to ingest a substance that makes you feel odd basically impacts brain function.
The 60’s and 70’s encompassed an awakening of the world to a number of funny feeling substances, and anyone who lived through it or who knows about life in those times knows that their use among adolescents and young adults was a widespread, inexpensive--financially speaking--way to get high. But there was a cost. A generation of young people exposed their brains to drugs because it felt good, not appreciably concerned about potential damage to their central nervous systems, or, more devastatingly, the well-being of their future offspring.
The newly graduated college coed, Class of 1974, unable to find a teaching position, waitresses to pay the rent.
Co-workers offer her some pot after the restaurant closes for the night.
She laments, what’s the harm?
During her blurry drive home, nearly blinded by oncoming headlights
she felt like the car was flying.
Grateful to arrive at her apartment in one piece, she buzzed through a whole bag of Ruffles,
evidenced by salty crumbs and an empty bag in her bed the next morning.
This will not happen again!
Over the past 10 years, a strong push toward legalizing the recreational use of marijuana has made headlines and great headway. In 2019 and 2020, several US states have made, or are in the process of making pot legal, with sights on substantially improving their state’s economy. In 2017, Canada removed the criminality from marijuana use, justified as a public safety measure by eliminating organized crime from the marijuana market. Few are speaking out loudly about the dangers inherent in recreational use of the drug.
Those who are concerned with the neurotoxic effects of its use-- medical, pharmacological, psychological, and social science researchers—are conducing well designed studies and their results document some significantly negative effects of recreational marijuana use. The debate, to legalize or not, fuels a discussion on some of the most compelling reasons to protect children, adolescents, and even young adults from exposure to this drug. Of note, one in five pregnant women use marijuana during pregnancy-- some report using it for nausea relief, perhaps ignorant to potential fetal to growth retardation and risk of impaired neurological development in the fetus.
We know that human brain development begins in fetal life and is not complete until at least 23 years of age. In fact, deleterious effects of cannabis have been documented in adults beyond age 23. This fact notwithstanding, in states where marijuana is legal, 21 years is the typical legal age for purchase and use.
Marijuana is often cited as the most frequently used recreational drug in western societies. Generally, many people are relatively unconcerned that it has significant negative effects. Many also believe that cannabis is neither habit forming nor capable of causing withdrawal with sustained abstinence. Research has disproven these ideas. There are likely great numbers of people who used the drug in the 60s and onward, who think that smoking pot did not affect them. But the effects of the drug can be subtle, such as a few IQ points in the wrong direction, or impaired ability to concentrate. It is conceivable that these old hippies actually do suffer central nervous system abnormalities and fail to connect them with smoking pot. Research continues to show not only the neurologic impacts of cannabis use, but that other body systems are also at risk. Cardiovascular disease, kidney and liver disease are among the conditions that may be associated with recreational cannabis.
There is a growing field of study on cannabis separate from documenting its untoward effects. Medicinal use of the substance has been documented as far back as centuries ago. Medicinal applications decreased in the mid 20th century, perhaps due to the rise in abuse among young people. There is a great deal of promise in managing a variety of disease processes with its appropriate prescription. Patients with chronic pain, intractable seizures, and loss of appetite due to cancer treatment are benefitting from medical marijuana. Exciting studies are in progress hoping to find ways to relieve pain in some degenerative neurologic disorders, such as Alzheimer’s Disease and Amyoptophic Lateral Sclerosis (ALS). It is being studied as a treatment for diseases of the liver, kidney, retina, and a host of other conditions.
According to multiple studies, recreational cannabis use, especially in the adolescent, increases the risk for development of psychiatric disorders in adulthood. These include behavioral deficits, pathological fear, and long-term anxiety disorders. Some experts believe that exposure to street use of the drug can impact both brain maturation and intellectual function.
A longitudinal study looked at alcohol and/or marijuana use in 3,800 students in Montreal, starting in the seventh grade, with annual reassessments over a four year period. The researchers identified year to year decrements in cognitive performance of students who used one or both drugs, adjusting for levels and frequency of use, implying cumulative effects with longer exposure. When looking at which of the two substances was more detrimental, alcohol was associated with fewer fatal consequences than cannabis. Cannabis was noted to have a worse effect on cognitive function, especially when used long-term.
A separate study comparing the impact of cannabis vs alcohol on the development of personality disorders, personality disorders were more common in those with cannabis dependence without alcohol than in alcohol dependence without cannabis. The study also highlighted that those with a cannabis use disorder generally receive less social support than those with alcohol use disorders, suggesting societal attitude differences between the two.
The Montreal study group showed, when comparing tenth grade students who used marijuana in the preceding one to two years, to seventh grade students who have never used it, the tenth graders made 25% more errors in one of the eight executive functions of the brain that were looked at, inhibitory control, or the ability to choose an appropriate behavior over an impulsive one. This forebodes a concerning trend, year over year, while adult supervision naturally decreases, for an increased risk of poor behavior choices. Consequently there is more opportunity for illicit access to and, therefore, prolonged use of the drug. Additional findings of this study included marijuana’s lasting impact on memory, perceptual reasoning, and cognitive development.
Adolescents, a group who, in their maturation process, are exposed to innumerable sources of stress—body image, social pressures, educational demands, financial challenges, family conflicts--may be significantly more vulnerable to the effects of habitual cannabis exposure than other sub groups A study published in the Journal of Neuropharmacology in 2019 investigated simultaneous use of THC and stress exposure in adolescent mice and demonstrated an absence of appropriate fear response in the same mice in adulthood, suggesting interference with the defense mechanism known as the fear circuit. This could be interpreted as a reason for, or an added propensity for excessive risk-taking behaviors in adolescents and young adults.
There is more to be concerned about. Based on epidemiological analyses, those who begin to use cannabis at an early age are known to be at risk for psychotic disorders. In fact, the risk for schizophrenia—a serious psychiatric disorder affecting how the individual interprets reality, and may involve hallucinations, delusions and disordered thinking and behavior—in cannabis users, is double that of the general population.
An interesting question within the broad spectrum of research on cannabis effects is whether or not these effects are reversible if the user abstains over extended periods of time, even for as briefly as 25 days. There are bodies of evidence supporting both reversibility and irreversibility of the damage caused, especially, by habitual use of cannabis, and any definitive conclusions have yet to be published. That said, some very convincing evidence supporting the irreversibility of brain changes was published in a comprehensive 2019 systematic literature review. The review identified 20 scientific studies on whether functional changes in the brain would persist following a period of abstinence from cannabis use. The research involved the use of MRI imaging during tasks that stimulated specific areas of the brain. The extensive analyses done to decipher the results strongly suggest that certain brain function changes caused by cannabis use are detectable, especially in the adolescent population, beyond the period of time when the drug is no longer detectable in urine samples, approximately 25 days after subject’s last reported dose.
The debate over the costs and benefits of legalizing marijuana may continue for some time, probably long after most states have changed the law. For now, the states have the right and the responsibility to decide on policies that govern their own constituents. The democracy we enjoy makes that so. But the evidence is strong, and therefore, as individuals everyone must be well educated and counseled so that they will make the most beneficial decisions for themselves, their families, and their communities.
Sources:
(The 1964 sixth grade class) personal testimony from a classmate.
(The newly graduated college coed,) personal testimony from the coed.
(Canada: legalization justification) Philip D. Harvey, Ph.D., Smoking and Cannabis and Acquired Impairments in Cognition: Starting Early Seems Like a Really Bad Idea, American Journal of Psychiatry 2019; 176:90-91.
Burggren, et al., Cannabis effects on brain structure, function, and cognition: considerations for medical uses of cannabis and its derivatives, American Journal of Drug and Alcohol Abuse 2019, 45(6), 563-579.
(Unborn fetuses exposed to cannabis in the womb) Henschke, P., Cannabis: Ancient friend or foe? What works and doesn’t work; Seminars in Fetal and Neonatal Medicine, 2019, 24(2), 149-154.
(One in five women use marijuana in pregnancy) Δ9-tetrahydrocannabinol exposure during rat pregnancy leads to symmetrical fetal growth restriction and labyrinth-specific vascular defects in the placenta, Scientific Reports, Volume 10, Issue 1, 1 December 2020, Article number 544
(Old hippies…suffer central nervous system disorders) Yarnell, et. Al., Substance Use Disorders in Later Life: A Review and Systhesis of the Literature of an Emerging Public Health Concern, American Journal of Geriatric Psychiatry, 2020, 28(2), 226-236
(Cardiovascular disease, kidney and liver disease are among the conditions) Park, et. Al., Cannabinoids and the kidney: Effects in health and disease, American Journal of Physiology – Renal Physiology, 2017, 313(5), F1124-F1132; Bondarenko, A.I., Cannabinoids and Cardiovascular System, Advances in Experimental Medicine and Biology, 2019, 1162, 63-87
(cannabis v alcohol and personality disorders) Cougle, et. Al., Personality disorders and social support in cannabis dependence: A comparison with alcohol dependence, Journal of Affective Disorders, 265, 2020, 26-31
Morin, et al., A population-based analysis of the relationship between substance use and adolescent cognitive development; American Journal of Psychiatry 2019; 176(2), 98-106.
(Strong support for irreversibility of neurotoxic effects) Blest-Hopley, et al., Regular cannabis use is associated with altered activation of central executive and default mode networks even after prolonged abstinence in adolescent users: Results from a complementary meta-analysis, Neuroscience and Biobehavioral Reviews, 2019, 96, 45-55.
(Medicinal use of [marijuana]) de Tommaso, et. Al., Therapeutic approach to pain in neurodegenerative diseases: current evidence and perspectives, Expert Review of Neurotherapeutics, 2017, 17(2), 143-153; Schwitzer, et. al., The Endocannabinoid System in the Retina: From Physiology to Practical and Therapeutic Applications, 2016, Neural Plasticity, 2016, 2916732; Kucerova, et.al., Therapeutic potential of cannabinoids in schizophrenia, 2014, Recent Patents on CNS Drug Discovery, 9(1), 13-25
(Adolescents may be significantly more vulnerable to the effects of habitual cannabis exposure) Saravia, et al., Concomitant THC and stress adolescent exposure induces impaired fear extinction and related neurobiological changes in adulthood, Neuropharmacology 2019, 144, 345-357.
(Two fold increase in risk for schizophrenia) Philip D. Harvey, Ph.D., Smoking and Cannabis and Acquired Impairments in Cognition: Starting Early Seems Like a Really Bad Idea, American Journal of Psychiatry 2019; 176:90-91.
(25% more errors in one of the eight executive functions) Philip D. Harvey, Ph.D., Smoking and Cannabis and Acquired Impairments in Cognition: Starting Early Seems Like a Really Bad Idea, American Journal of Psychiatry 2019; 176:90-91.
(Used to treat some, often debilitating medical conditions, such as chronic pain and intractable seizures) deShazo, et al., Marujuana’s Effects on Brain Structure and Function: What Do We Know and What Should We Do? A Brief Review and Commentary; American Journal of Medicine 2019; 132(3), 281-285.
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