The negative impact on the brain leads to great concerns in regard to normalizing recreational use of marijuana for the general public.

After researching this issue from a professional perspective, I believe there are both positive and negative factors to consider before choosing to use marijuana in any form.


Medical Conditions:  The National Academy of Sciences, Engineering, and Medicine’s extensive 2017 review of the health effects of cannabinoids found that only three therapeutic uses had conclusive research support: 

1) treating some forms of chronic pain, 2) decreasing spasticity associated with multiple sclerosis, and 3) reducing nausea associated with chemotherapy. Other possible conditions being researched are glaucoma, epilepsy, wasting syndrome associated with AIDS, and inflammation (as in rheumatoid arthritis, Crohn’s disease, and ulcerative colitis).

Thousands of studies on the benefits of marijuana’s components are ongoing, with potential benefits to many other conditions such as Alzheimer’s disease and neuropathy in diabetes.

CBD Oil: CBD oil is a non-THC part of marijuana that does not get a person “high”. Investigations are ongoing as to whether CBD oil provides equal benefit, or whether THC – the part that gets you “high”- is more effective for treating various conditions, especially pain. CBD oil as a safe alternative to THC is promising, although most companies get CBD from hemp as opposed to marijuana. Also, caution is needed since investigations show great variations in actual dosage compared to labels among different companies selling it.  

High quality CBD oil has much testimonial support as an alternative to THC, and claims of an improved pain management effect with a small dose of THC added that is insufficient to get a person “high”.  This may be useful in the treatment of conditions such as problems with anxiety disorders or even Post-Traumatic Stress Disorder.  Rigorous studies are needed before empirical conclusions can be made. Quality control problems and lack of FDA or NIH approvals cause many to be cautious at present.  Due to THC in many CBD products, stories of many people having employment problems from positive drug tests are also of real concern for occupations such as truck drivers and police officers.


Risk of Psychosis? Cannabis use in teens increases the risk for psychosis.  Clients with bipolar disorder and schizophrenia experience a more severe course of illness and poorer life functioning.  The research shows, however, that other genetic factors, such as family members who have these conditions, may bring an even greater increase in risk.  Genetic vulnerability to this problem certainly indicates that those with hereditary risk factors should avoid marijuana use. 

Brain Function: Cannabis use in teens results in lower cognitive functioning and is also correlated with lower prestige occupations than their parents, lower income, higher unemployment, a greater need for socioeconomic assistance, increased criminal behavior, and lower satisfaction with life.  Brain scans show decreased blood flow to the brain indicating lesser brain function, decreased IQ, and increasing concerns regarding early Alzheimer’s disease. 

Adult Health Consequences: Long term daily cannabis users experience the most harmful effects, while these are uncommon for occasional recreational users. Inflammation of the large airways, lung hyperinflation, chronic bronchitis, increased respiratory infections, pneumonia, higher risk of stroke and heart attacks, are all noted in some correlational research with marijuana.  There is also concern for the prenatal brain development of unborn children.  Physically, the most frequent problem experienced is gum disease.  Research related to lung cancer is confounded by other variables, such as cigarette use.  Tobacco is clearly related to lung and other cancers, and many believe the evidence points to the same problem with marijuana.  Others argue for a protection benefit from some cancers, however, due to our endocannabinoid system and preliminary research.  

Addiction Potential: Nine percent of those who experiment with marijuana will develop an “addiction” to it.  That rises to about 17% for those who start using marijuana as teenagers, and 50% for those who smoke pot daily.  The teenage brain is still developing, so introduction of psychoactive substances at this age is seen as very problematic for healthy development.  Learning and memory portions of the brain are affected, as are those areas involved in alertness, self-conscious awareness, and impulse control.  The healthy development of children and youth is hindered through the influence of marijuana which studies show make them more vulnerable to addiction to other substances.

Brain scans show the same patterns for marijuana as other addictions. There is a “cannabis withdrawal syndrome” with irritability, sleep difficulty, anxiety, and craving which contributes to the addiction process and relapse.  

Gateway Drug: Increased use of marijuana does predict an increased risk of the use of other illicit drugs.  Research shows that marijuana decreases the reactivity of the dopamine neurons that modulate the brain’s reward regions.  In other words, the brain becomes more susceptible to addiction to other drugs, making marijuana a “gateway drug” both socially and physiologically.  The marijuana primes the brain for a heightened response to other drugs.  It is no surprise that research has shown that smoking marijuana doubles the risk for opioid addiction later in life.

Impaired Driving: A 2012 meta-analysis of the data concluded with:  “Drivers who test positive for marijuana or self–report using marijuana are more than twice as likely as other drivers to be involved in motor vehicle crashes.” Another study reported it “doubles the risk of a motor vehicle accident.” The evidence is clear from research that marijuana impairs perception of time and speed, reaction time, motor coordination, and attentiveness.     

What are your thoughts about legalization? Write me with your feedback or to request references.

Ronald S. Newman, Ph.D. is a psychologist in Mays Landing on Route 50 who can be reached at:, or 609-567-9022.      

Originally written for the Hammonton Gazette, June 2019, who have first rights to publish.

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