Is Cannabis a Safe Alternative to Alcohol for Your Teen?

Abundant evidence highlights the risk THC poses for developing brains.

Posted Jul 31, 2019

Psychotic symptoms, such as delusions (firmly held false beliefs) and hallucinations (false sensory experiences) are hallmarks of schizophrenia, but they are also associated with bipolar disorder, delusional disorder, schizoaffective disorder, and sometimes severe depression. Increasingly, individuals who experience psychotic symptoms share an important risk factor: They regularly smoked high-potency cannabis, especially from an early age.

The National Health Service (NHS) in the UK, “overwhelmed” by cannabis-related psychosis, sometimes occurring after the first use, recently opened clinics to treat tens of thousands of young people. NHS clinicians estimate that 25 percent would not have developed psychosis but for their cannabis use.  

Parents are often shocked to learn there is a correlation between psychosis and cannabis. They’ve viewed cannabis as benign, like oregano... a safe, "natural product" that adds a little spice to life. Many have encouraged their children to smoke pot, seeing it as a safer alternative to alcohol.

Cannabis contains more than 500 chemicals, including the “cannabinoids” tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is responsible for the high, but what is available on the schoolyard is not your grandparents' pot anymore.

For decades, cannabis has been bred to increase its potency, from 1 to 4 percent THC to 20 to 40 percent or more, depending on the product. Highly concentrated “shatter” is produced by using solvents like butane and can contain more than 80 percent THC, which is more impairing, more addictive, and more dangerous for the developing brain.

Conversely, CBD reduces the impact of THC and likely contributes to its medicinal benefits. CBD has quality scientific research demonstrating its anti-inflammatory, analgesic, anticonvulsant, antipsychotic, and antianxiety properties. The amount of CBD found in recreational cannabis has steadily declined, which has heightened its pro-psychotic effects, due to unopposed THC.

Scientific evidence is abundant, compiled over decades, demonstrating the serious risks posed by cannabis, particularly for developing brains. Despite the science, myths abound, and those who champion the safety of cannabis propagate false narratives and attack those who dare to offer an evidence-based alternative view.

Many parents believe cannabis is a safe alternative to alcohol for their teen.
Source: designecologist/Pexels

Myth: Cannabis is safe, because it's a "natural product."

Other "natural products" include arsenic, pufferfish toxin, and tobacco, which causes cancer from mouth to anus and everywhere in between. Frequent smoke inhalation, whether because you’re smoking cannabis or salmon, contains toxins linked to cancer and chronic lung diseases. Beyond the risk of smoke inhalation, THC use has been associated with lowering IQ, neurotoxicity (brain cell damage), mental illness, motor vehicle accidents (MVAs), and much more.

Myth: Cannabis makes me a safer driver

The comical part two of this comment is, “…because I drive more slowly”. Any mind-altering substance impacts driving. While nearly 80 percent of us believe alcohol impairs drivers, only 30 percent believe the same of cannabis. Yet just like alcohol, cannabis affects the brain functions required for safe driving (judgment, attention, vision, reaction time, motor coordination), rendering cannabis-impaired drivers less able to adapt to sudden changes while driving.

There is a direct correlation between impaired driving and blood THC levels, and research has demonstrated that cannabis intoxication doubles the risk of causing an MVA. A 2014 study found that since legalization in Colorado, there has been an increase in marijuana-positive drivers involved in fatal MVAs.

Because many drivers don't believe cannabis is impairing, they're more likely to drive high. A 2013 study found that if drivers feel confident they won't be harshly judged by their peers, this sharply increases the likelihood they'll drive high, especially if they don't believe their driving performance is impaired.

Myth: Cannabis is a safer alternative to alcohol for teens.

Comparing favorably to alcohol—a substance associated with serious medical and social problems—isn't much to crow about, but is cannabis truly a safer alternative?

The impact of THC on a developing brain can be profound and life-altering. Adolescence is a time of massive brain remodeling when brain cells (neurons) are pruned and specialized connections are made between critical brain regions. Serious mental illnesses, such as schizophrenia, often present during this remodeling phase.

2016 study reviewed 31 scientific papers and reported compelling evidence that high THC levels found in street cannabis alter brain structure, size, and function, especially for frequent, heavy users. The amount of damage is directly correlated with THC potency, frequency of use, and the age when cannabis use begins.

Neurons in brain areas rich in cannabinoid (CB1) receptors, including the prefrontal cortex (PFC), hippocampus, and amygdala, may be damaged or destroyed by THC.

The PFC is the brain’s executive, necessary for mature adult behavior: organizing, planning, forward-thinking, and critical thinking. If you’ve parented a teenager, you know their PFC isn't fully developed; for many, it isn’t fully functional until age 25.

Fact: Early and frequent cannabis use is linked to psychotic disorders like schizophrenia.

Neurotoxicity is most impactful when THC is used during the time of critical brain remodeling during adolescence. We cannot state that cannabis causes schizophrenia, because most users don’t develop the disorder. However, there is a significant correlation between cannabis use and the onset of psychotic symptoms up to six years earlier in those who start smoking before age 15.

Those six years are a big deal because of greater emotional and social development before the onset of psychotic symptoms is associated with less functional impairment. If avoiding cannabis delays the onset of schizophrenia by several years, this has a tremendous impact on educational attainment, relationships, independence, financial stability, and treatment engagement.

Myth: I know my kid’s brain isn’t vulnerable.

Some brains are more vulnerable than others, but the trouble is, we don't always know whose brain is at high risk. Cannabis use as an adult is a personal decision. Most agree that adults should be free to decide how they wish to treat their body, so long as they don’t cause harm to others.

However, when advising our children, we must consider what they stand to lose and what the cannabis seller stands to gain by attempting to discredit the science. There is simply no cogent, evidence-based argument that recreational cannabis benefits teens, and for a vulnerable brain, the harms can be devastating.


Madeline H. Meier, Avshalom Caspi, Antony Ambler, et al. (2012) Persistent cannabis users show neuropsychological decline from childhood to midlife PNAS October 2, 2012, 109 (40) E2657-E2664

Ksir C, Hart CL. (2016) Cannabis and Psychosis: a Critical Overview of the Relationship. Curr Psychiatry Rep. 2016 Feb;18(2):12. 

Gage SH, Hickman M, Zammit S. (2016) Association Between Cannabis and Psychosis: Epidemiologic Evidence. Biol Psychiatry. 2016 Apr 1;79(7):549-56. 

Marconi A, Di Forti M, Lewis CM, et al. (2016) Meta-analysis of the Association Between the Level of Cannabis Use and Risk.Schizophr Bull. 2016 Sep;42(5):1262-9.