Source: Dr. Liji Thomas, MD, "Dangers of recreational/medical cannabis use," News Medical and Life Sciences, 26 October 2022.
More people are using marijuana and starting at a younger age.
"Now that many American states have legalized cannabis, the already high rate of cannabis usage is increasing from ages as young as 16 years."
Current studies on marijuana's effects are flawed.
Medical use of cannabis is "taking place in the context of limited evidence that cannabis is safe. Furthermore, studies are limited by a reliance on a single source of cannabis from federal stocks, recall bias, small sample sizes, and poor external validity. An earlier Cochrane review in 2017 reports that most studies were of low to moderate quality."
Marijuana has limited use in pain management and comes with significant side effects.
"... the global impression of any change in pain management was very low among patients, with adverse effects of cannabis use accounting for multiple withdrawals from studies on medical cannabis."
Marijuana is linked to psychiatric disorders.
Medical cannabis "appeared to impact the nervous system, with a higher risk of psychiatric disorders. Long-term risks have been poorly assessed. Furthermore, some authors have concluded that the cost-benefit ratio of medical cannabis is unfavorable."
Marijuana negatively impacts memory, attention, and decision-making abilities.
"Cannabis users tend to show defects in executive function, with poorer memory and attention than non-users. This appears to be dose-dependent and affects cognition, reward, and motivation."
"Young adults with cannabis use disorder (CUD) could have cognitive impairments due to disorders of the emotional domain. This reduces normal cognitive control and decision-making capacity in emotionally strenuous situations."
"Studies of brain electrical activity suggest that cannabis users have increased cortical activation at rest, perhaps because the normal inhibition of unnecessary processes that create background noise and reduce brain efficiency is impaired by cannabis."
The negative effects of marijuana on the brain show up soon and lasts for a long time.
"Acute cannabis use affects working, verbal and visual memory, as well as episodic memory and attention, with higher impulsivity. In fact, small changes are detectable within a week of heavy cannabis use. Tests of memory and learning consistently produce poorer results among cannabis users. Chronic use of cannabis tends to impair memory ..."
"Chronic cannabis use may permanently alter cognition by changing brain processing in pathways like the prefrontal-limbic system network. Abstinence for over one month was not associated with a better response to emotional stimuli in chronic users with dependence."
Marijuana impairs physical reaction times, especially in situations that demand long-term attention (such as driving).
"Chronic use of cannabis tends to ... [induce] significant brain dysfunction that affects visual-motor pathways. If chronic users who abstained for an average of 15 hours are compared with chronic tobacco users, the former were shown to have worse learning and recall memory, with more interference and greater forgetfulness. Reaction times were also longer among chronic cannabis users, particularly when sustained attention was required."
"The association of poor working memory, a brain function that develops mostly in adolescence, occurs more significantly in frequent adolescent cannabis users as compared to adults. ... [This] may indicate a risk factor for cannabis use since it did not show any difference between single- and repeated-use cases."
Marijuana is associated with increased throat cancer
"Patients with throat cancer are more likely to use cannabis ... Cannabis smoking produces toxins that can produce cancer of the head and neck, as well as immunosuppressants and mutagens."