The therapeutic application of cannabis has become increasingly prevalent across developed nations, yet the scientific evidence supporting its medical use remains surprisingly limited. A recent JAMA Clinical Reviews podcast featuring Dr Kevin Hill from Harvard Medical School reveals critical information that healthcare professionals and patients need to understand about the therapeutic use of cannabis and its associated risks.
According to recent data, approximately 27% of adults in the United States and Canada have used cannabis for medical purposes, whilst just over 10% have tried cannabidiol (CBD) for therapeutic reasons. This widespread adoption has occurred despite minimal regulatory approval and mounting evidence of significant health risks.
Understanding Cannabis and Its Components
Cannabis is a complex plant containing hundreds of chemical compounds, including flavonoids, terpenes, and cannabinoids. Whilst over 140 cannabinoids exist within the plant, medical discussions typically focus on two: delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the psychoactive compound responsible for the “high” associated with cannabis use and can also trigger psychotic episodes. CBD, conversely, is not intoxicating, though it does affect how users feel.
The complexity of the therapeutic use of cannabis stems partly from its numerous formulations. People can smoke cannabis flower, consume edible products, vaporise the substance, or apply topical ointments. Each formulation delivers different potencies and onsets of action, with THC content being the critical variable across all forms.
Limited FDA Approvals for Therapeutic Use of Cannabis
Currently, only three cannabinoid medications have received approval from the US Food and Drug Administration. Dronabinol (pure THC) and nabilone (a CB1 receptor agonist) are approved for treating nausea and vomiting associated with cancer chemotherapy, as well as appetite stimulation in conditions like HIV. In 2018, one particular CBD formulation gained approval for treating two paediatric epilepsy conditions (Lennox-Gastaut and Dravet syndrome) and seizures associated with tuberous sclerosis in adults.
These limited approvals stand in stark contrast to the numerous conditions for which people currently use cannabis, often without solid scientific evidence supporting its efficacy.
Rising Potency and Escalating Risks
One of the most concerning trends in medicinal cannabis use involves dramatically increasing potency levels. During the 1960s, 1970s, and 1980s, typical cannabis contained three to four percent THC. Published research from the University of Mississippi now shows typical potency hovering near 20 percent THC. This fivefold increase has profound implications for both acute and chronic health effects.
Acute risks associated with cannabis use include impaired judgement, motor skill deficits, elevated heart rate, and transient psychosis. These immediate effects can compromise driving ability and decision-making, posing risks not only to users but to those around them.
Chronic Health Effects and Medicinal Cannabis
The chronic effects of cannabis prove particularly problematic for individuals using daily or near-daily. Dr Hill emphasised that most adverse effects relate to THC rather than CBD, though CBD can cause problems as well. Brain-related complications include addiction, cannabis hyperemesis syndrome (severe cyclical vomiting), and worsening of various psychiatric conditions.
Recent epidemiological research published in JAMA Psychiatry revealed a striking statistic: 34.8% of adult cannabis users develop cannabis use disorder. This represents a significant increase from previous estimates of 10 to 30 percent. For those using cannabis for medical purposes specifically, approximately 29% develop use disorder.
Physical health impacts have become increasingly well-defined through research. Cardiovascular adverse effects, pulmonary complications, and chronic neurocognitive deficits all occur with regular cannabis use. These risks accumulate over time, particularly amongst daily users.
Therapeutic Use of Cannabis and Addiction Risk
Cannabis use disorder represents a significant concern that clinicians must monitor carefully. Warning signs include tolerance (requiring increasingly larger amounts to achieve the same effect), withdrawal symptoms upon cessation, and spending excessive time obtaining or using cannabis at the expense of work, school, or relationship responsibilities.
Diagnostic criteria specify that experiencing two or more of eleven specific factors within a 12-month period indicates cannabis use disorder. Healthcare professionals working with patients considering the therapeutic use of cannabis must remain vigilant for these signs, as addiction can develop even when use begins for legitimate medical reasons.
Particular Concerns for Young People
The developing brain faces unique vulnerabilities to cannabis exposure. Human brains continue developing into the mid-20s, and research demonstrates that early and regular cannabis use can significantly impair cognitive abilities. A 2012 study published in the Proceedings of the National Academy of Sciences found that young people using cannabis daily or near-daily experienced up to an eight-point decline in IQ over time. This represents more than one standard deviation, a statistically and clinically significant reduction.
These findings underscore the importance of preventing cannabis use amongst adolescents and young adults, whose neural development remains incomplete and particularly susceptible to disruption.
The Evidence Gap in Medicinal Cannabis Use
A critical issue confronting healthcare professionals involves patients using cannabis for conditions lacking solid scientific support. Whilst people suffering from chronic medical conditions naturally seek relief, the evidence base for the therapeutic use of cannabis remains limited primarily to the FDA-approved conditions mentioned earlier.
Dr Hill emphasised the importance of clinicians engaging in evidence-based conversations with patients. When patients express determination to use cannabis despite limited evidence, healthcare professionals face the challenging task of providing informed guidance whilst acknowledging the significant risks involved.
Concerns About Concurrent Substance Use
Cannabis use becomes particularly dangerous when combined with alcohol or benzodiazepines. These combinations amplify impairment and increase risks of accidents, respiratory depression, and poor decision-making. Healthcare professionals must clearly communicate these dangers to any patients considering medicinal cannabis.
Changing Legal Landscape and Public Health Implications
As of the podcast recording, 38 US states had implemented medical cannabis policies, with 24 states legalising recreational use. This shifting legal landscape has contributed to increased cannabis use overall, creating what Dr Hill described as a situation where “the train’s left the station.”
However, legal availability should not be confused with medical safety or efficacy. The rise in cannabis use has coincided with increases in cannabis use disorder, emergency department visits related to cannabis, and various other adverse outcomes.
Clinical Guidance for Healthcare Professionals
Healthcare professionals must balance acknowledging patient autonomy with providing evidence-based guidance about the therapeutic use of cannabis. Key points for clinical discussions include the limited scope of FDA approvals for cannabinoid medications, the lack of robust evidence for most conditions people treat with cannabis, the significant risk of developing cannabis use disorder (affecting roughly one-third of users), the particular dangers for young people whose brains are still developing, and the inadequacy of current treatments for cannabis use disorder.
Dr Hill noted that whilst many adverse effects exist, addiction itself is on the rise, and the medical community lacks effective treatments for cannabis use disorder. This reality makes prevention all the more critical.
Understanding the Risks
The therapeutic use of cannabis and cannabinoids represents a complex intersection of patient demand, limited scientific evidence, changing social attitudes, and concerning health risks. Whilst three FDA-approved cannabinoid medications exist for specific conditions, widespread cannabis use for medical purposes extends far beyond these narrow indications.
The dramatic increase in cannabis potency over recent decades, combined with rising rates of cannabis use disorder, creates a public health challenge that demands attention. Healthcare professionals must remain informed about both the limited evidence supporting medicinal cannabis and the well-documented risks associated with regular consumption.
For young people in particular, the potential for lasting cognitive impairment and the high risk of developing addiction make cannabis use a serious concern. As legal barriers continue falling, the importance of education about risks becomes paramount.
Understanding these realities allows healthcare professionals to engage patients in meaningful, evidence-based discussions about the therapeutic use of cannabis. Such conversations must acknowledge patient suffering and desire for relief whilst honestly presenting the limited evidence base and substantial risks that accompany cannabis consumption.
(Source: WRD NEWS)
