Walk into any bar or public place and poll opinions about cannabis and there will be a different opinion for each person polled. Some opinions will be well-informed from reputable sources, while others will simply be formed without any basis. To be sure, research and conclusions based on research are difficult given the long history of illegality. However, there is a groundswell of opinion that cannabis is good and should be legalized. Many states in America and Australia have embarked on the path of legalizing cannabis. Other countries are following suit or considering options. So what is the position now? Is it good or not?
The National Academy of Sciences published a 487-page report this year (NAP Report) on the current state of the evidence on the subject. Many government grants supported the work of the committee, an eminent collection of 16 professors. They were supported by 15 academic reviewers and some 700 relevant publications were considered. Therefore, the report is considered state of the art in medical and recreational use. This article relies heavily on this resource.
The term cannabis is used here loosely to represent cannabis and marijuana, the latter coming from a different part of the plant. There are over 100 chemical compounds found in cannabis, each potentially offering different benefits or risks.
CLINICAL INDICATIONS
A person who is “high” from smoking cannabis may experience a state of euphoria in which time is irrelevant, music and colors become more important, and the person may get the “bites”, wanting to eat sweet and fatty foods. This is often associated with impaired motor skills and perception. When high blood concentrations are reached, paranoid thoughts, hallucinations, and panic attacks can characterize your “trip.”
PURITY
In the vernacular, cannabis is often characterized as “good shit” and “bad shit”, alluding to the widespread practice of contamination. Contaminants can come from soil quality (for example, pesticides and heavy metals) or added later. Sometimes lead particles or tiny glass beads increase the weight sold.
THERAPEUTIC EFFECTS
A random selection of therapeutic effects appears here in the context of their evidence status. Some of the effects will show up as beneficial, while others carry risks. Some effects are barely distinguishable from research placebos.
- Cannabis in the treatment of epilepsy is inconclusive due to insufficient evidence.
- Nausea and vomiting caused by chemotherapy can be relieved with oral cannabis.
- A reduction in pain severity in patients with chronic pain is a likely result of cannabis use.
- Spasticity in patients with multiple sclerosis (MS) was reported as improvements in symptoms.
- Increased appetite and decreased weight loss have been shown in patients with HIV/ADS in limited evidence.
- Based on limited evidence, cannabis is ineffective in the treatment of glaucoma.
- Based on limited evidence, cannabis is effective in the treatment of Tourette’s syndrome.
- Cannabis has helped post-traumatic disorder in only one reported trial.
- Limited statistical evidence points to better outcomes for traumatic brain injury.
- There is not enough evidence to say that cannabis can help Parkinson’s disease.
- Limited evidence dashed hopes that cannabis might help improve symptoms in dementia patients.
- Limited statistical evidence can be found to support an association between cannabis smoking and heart attack.
- Based on limited evidence, cannabis is ineffective for treating depression
- Evidence of reduced risk of metabolic problems (diabetes, etc.) is limited and statistical.
- Cannabis may help social anxiety disorders, although the evidence is limited. Asthma and cannabis use are not well supported by the evidence either for or against.
- Cannabis has helped post-traumatic disorder in only one reported trial.
- The conclusion that cannabis can help people with schizophrenia cannot be supported or refuted based on the limited nature of the evidence.
- There is moderate evidence of better short-term sleep outcomes for people with sleep disorders.
- Pregnancy and cannabis smoking are correlated with reduced birth weight of the baby.
- The evidence for stroke caused by cannabis use is limited and statistical.
- Cannabis addiction and entry problems are complex, taking into account many variables that are beyond the scope of this article. These issues are analyzed in detail in the PAN report.
CANCER
The NAP report highlights the following findings on the subject of cancer:
- Evidence suggests that smoking cannabis does not increase the risk of certain types of cancer (ie, lung, head, and neck) in adults.
- There is modest evidence that cannabis use is associated with a subtype of testicular cancer.
- There is minimal evidence that parental cannabis use during pregnancy is associated with an increased risk of cancer in the offspring.
RESPIRATORY DISEASE
The NAP report highlights the following findings on the topic of respiratory diseases:
- Regular cannabis smoking is associated with chronic cough and phlegm production.
- Quitting cannabis is likely to reduce chronic cough and phlegm production.
- It is unclear whether cannabis use is associated with chronic obstructive pulmonary disease, asthma, or worsening lung function.
IMMUNE SYSTEM
The NAP report highlights the following findings on the subject of the human immune system:
- There is a paucity of data on the effects of cannabis or cannabinoid-based therapies on the human immune system.
- There are insufficient data to draw general conclusions about the effects of cannabis smoke or cannabinoids on immune competence.
- There is limited evidence to suggest that regular exposure to cannabis smoke may have anti-inflammatory activity.
- There is insufficient evidence to support or refute a statistical association between cannabis or cannabinoid use and adverse effects on immune status in people with HIV.
MORTALITY
The NAP report highlights the following findings on the subject of increased risk of death or injury:
- Using cannabis before driving increases the risk of being involved in a car accident.
- In states where cannabis use is legal, there is an increased risk of unintentional cannabis overdose injuries among children.
- It is unclear whether and how cannabis use is associated with all-cause mortality or occupational injuries.
BRAIN FUNCTION
The NAP report highlights the following findings on the topic of cognitive performance and mental health:
- Recent cannabis use affects performance in the cognitive domains of learning, memory, and attention. Recent use can be defined as cannabis use within 24 hours of assessment.
- A limited number of studies suggest that there are deficits in the cognitive domains of learning, memory, and attention in people who have stopped smoking cannabis.
- Cannabis use during adolescence is associated with impairments in later academic achievement and education, employment and earnings, and social relationships and social roles.
- Cannabis use is likely to increase the risk of developing schizophrenia and other psychoses; the greater the use, the greater the risk.
- In people with schizophrenia and other psychoses, a history of cannabis use may be related to better performance on learning and memory tasks.
- Cannabis use does not appear to increase the likelihood of developing depression, anxiety, and post-traumatic stress disorder.
- For people diagnosed with bipolar disorders, near-daily cannabis use may be associated with greater symptoms of bipolar disorder than for non-users.
- Heavy cannabis users are more likely to report suicidal thoughts than non-users.
- Regular cannabis use is likely to increase the risk of developing social anxiety disorder.
It should be reasonably clear from the above that cannabis is not the magic wand for all health problems that some well-intentioned but misguided cannabis advocates would have us believe. However, the product offers a lot of hope. Solid research can help clarify issues. The PAN report is a solid step in the right direction. Unfortunately, there are still many barriers to research on this amazing drug. Over time, the benefits and risks will be better understood. Confidence in the product will increase and many of the barriers, social and academic, will fall in the way.