Medicinal Benefits of Cannabis
Favorable opinions on the health benefits of cannabis have recently triggered the escalating medicinal use of cannabis. This situation has been reinforced by promising reports of the clinical outcome of the treatment of many diseases, even though many of these reports involve anecdotal experiences. Media reports describe thought leaders who have changed their minds about the value of cannabis as a medicinal agent. Most notable among this group is the positive opinion about medical marijuana expressed by medical correspondents. These individuals have highlighted the fact that until recently only approximately six percent of studies examined the health benefits of cannabis. In comparison, there is a much larger amount of research on its adverse effects. This situation has created "skewed" opinions that influence the evaluation of cannabis-use outcomes.
The health benefits of marijuana use have been summarized by several authors.5-7, 9, 10-13 These disease state or condition specific applications of cannabis are summarized in Table 1 and reviewed in reference 13.
Table 1. A List of Some of the Principal Health Benefits of Cannabis .pdf
Medicinal Futures of Cannabis
Medical cannabis use and further research on new cannabis drugs has produced encouraging results and some concerns. Cannabis contains a highly complex collection of different chemicals with diverse clinical effects. This knowledge has been used to support the preferential use of cannabis (marijuana) in its more natural (whole herbal) form, rather than when it is taken as isolated components of the plant (e.g. THC or its analogues or CBD, available alone in certain pharmaceuticals). It appears that the inevitable development of many regulatory-approved pharmaceutical-types of cannabinoid products will occur within five to ten years. Protagonists of cannabis use argue that its safety and effectiveness have been substantiated in a variety of medical or recreational circumstances, but no pharmaceutical agent is completely without adverse effects, especially if used inappropriately. Claims of universal safety of cannabis serve to mislead the public because, at present, we cannot define many of the potential outcomes of the widespread use of cannabis in society, especially with its long-term use in young people.
Thoughtful physicians and regulators have proposed that the ideal scientific and regulatory approaches to cannabis use should stress that it is shown to be safe and effective for each of the indications for which it is considered to have potential benefit. The emerging legislation that governs marijuana availability makes these prudent approaches in approval processes appear impractical or of diminished importance; and they are claimed by some to be increasingly redundant. These circumstances have generated much disagreement, especially among scientists and physicians.
Several scholarly articles have appeared on the future of cannabis as medicine.1-7 Some of these articles argue that cannabis is much safer than many commonly available medications. Furthermore, cannabis use has been considered to be relatively safe in comparison with the adverse effects of chronic alcohol intake. However, there is inherent fallacy in using examples of "worse" substances of potential abuse, e.g. alcohol, to justify cannabis use itself. It is the outcome of the use of cannabis itself that is the real issue to be examined in risk/benefit assessments.
Modern trends to "pharmaceuticalize" cannabis have not tended to result in the development of drugs that can out-perform the complex actions of intact, whole, herbal marijuana. As noted earlier, such differences are dependent to a major degree on the content of various cannabinoids and other compounds that account for the overall "entourage effects" of herbal cannabis. As mentioned previously, the "entourage effect" means, in simple terms, that the many natural components of cannabis work best together (synergy).8
Many scientists and physicians express their confidence that herbal marijuana use is now well established with adequate justification in certain circumstances.1-7,10-13 In addition, it is predicted that pharmaceutical discoveries of the actions of cannabinoids will lead to the development of a range of drugs with diverse, beneficial, therapeutic applications. That said, there is some residual doubt that these "cannabinoid pharmaceuticals" will be able to have the same degree of applicability, effectiveness, and safety that has been experienced with whole herbal cannabis. While a current public perception of the superior effects of cannabis smoking often exists, the downside risks are the vascular and pulmonary effects of smoking and other problems.
Cannabis: Research Problems
Studies of the health benefits or adverse consequences of cannabis use are clouded often by confounding factors. The heavy cannabis user is likely to engage in adverse lifestyle, compounded by common types of substance abuse such as tobacco, alcohol and use of other illicit drugs. To separate out contributory factors that alter health status in cannabis research has proven to be difficult. As discussed earlier, studies that show correlation of cannabis use with disease often fail to establish causal links. Furthermore, there is often a concern that adverse health findings could antedate cannabis use or even operate in a causal manner to drive cannabis use.
Associations between cannabis use and adverse health effects are clear in many studies, but it is stressed repeatedly in medical literature that evidence of causality is often missing.1-12 This situation can only be cured by prospective or longitudinal studies that have been difficult to perform previously because of the many years of prohibition of cannabis use. There is difficulty in being able to define clear, cause-and-effect relationships in many studies, especially when research has been retrospective.
W. Hall and L. Degenhardt9 have reviewed the adverse effects of chronic cannabis use and summarized them by probability of occurrences. See Table 2.
Table 2. The Adverse Effects of Cannabis Use, Stratified by Existing Evidence to Invoke Causal Relationships .pdf
Summary of Problems with Cannabis Research
Several problems exist with medical cannabis research.1-12 These problems must be kept in mind when interpreting study outcome data. Studies about the health consequences of cannabis use often display disadvantages and limitations that interfere with the development of firm conclusions. As mentioned earlier and repeatedly, in most circumstances, studies are based upon "associations" or correlations of varying strength. This means that several factors may account for the study outcome and the demonstration of a clear cause and effect relationship cannot be defined. Other circumstances operate with "chicken and egg arguments" about what came first. For example, outcomes may be related to the presence of pre-existing disorders or diseases in the study populations.
Prospective or longitudinal studies that examine potential causal relationships are much more valuable than correlative studies. Of course, these types of studies to show cause and effect are increasing but difficult to perform. The "prohibition" of cannabis use in the past has restricted this type of valuable research.1-7,13
Stephen Holt, MD, DSc, PhD, LLD, DNM, is a best-selling author. He has received many awards for teaching and research. He holds the appointment as Distinguished Professor of Medicine (Emeritus) NYCPM and has many citations of his books and articles in medical literature. His book, The Cannabis Revolution (What you need to know), was released in 2016, and is available at www.cannabisrevolution.org.