Ganja use, the law, and long-term effects

Dr Derrick Aarons

Sunday, February 04, 2018

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Currently nine states in the USA have legalised the recreational use of marijuana (ganja) within their jurisdictions. However, in the remaining 42 states and at the federal level in the USA, marijuana is still illegal and so any possession is a criminal offence with specific consequences to be imposed by the courts.

Many of the US states that have enacted such legislation have addressed the matter only at the personal level for those above the age of 21 years, and so they still do not permit any commercial trade in marijuana. The governor of Vermont, the most recent state to pass such a legislation, informed that he believed that what people do behind closed doors and on private property was their choice, as long as it did not negatively impact the health and safety of others, especially children.

Jamaica's dilemma

Jamaica has not legalised ganja as those nine US states have done, but rather has simply decriminalised the possession of 2 oz. or less of the plant. This does not mean that a person is permitted by law to use ganja, but rather, that if they are found with it, they will pay a fine instead of being charged with a criminal offence. Under this new dispensation, possession of ganja is thus a civil violation and not a criminal one.

Unfortunately, the latter point was not emphasised greatly enough in the period leading up to the decriminalisation of ganja in Jamaica in 2015, and so there is now the pervasive belief, particularly among the young who suffer the most damage through its adverse effects on their learning in school, that it is now legal to possess and use ganja in Jamaica!

Cardiovascular effects

With the rise in users of marijuana/ganja in recent decades, medical scientists have called for the need to perform robust longitudinal research studies that adequately characterise exposure to marijuana/ganja (and the different forms in which it is being used), especially among an aging population, to further our understanding of the effects on health of chronic marijuana/ganja use.

Large-scale observational studies are the best to achieve this, and with more jurisdictions worldwide legalizing marijuana use, gathering this information becomes more crucial than ever.

An analysis of published articles on the effects of long-term use of marijuana on cardiovascular risk factors was published in the January 2018 edition of the medical journal Annals of Internal Medicine, and found that there were not enough articles of good quality and quantity to draw conclusions. Many articles in the lay press have suggested to the public that marijuana use may have benefits on the cardiovascular system, reduce blood pressure, stabilise blood sugar levels, and improve cholesterol profiles. However, the researchers from the Wright Center for Graduate Medical Education in Scranton, Pennsylvania, USA, and colleagues at the University of California in San Francisco and the San Francisco Veterans Affairs Medical Center, found in their analysis that there was insufficient evidence of good research conducted to support these claims.

Insufficient research

In their review of the literature from January 1975 to September 2017, they found only 24 observational studies (with only two interventional and nine prospective studies) written on the use of marijuana, whether as a plant or as a pharmaceutical (drug). Six of the studies that suggested metabolic benefits from marijuana use were cross-sectional (done at just one period in time), and most had small sample sizes and included only one-time assessment of marijuana exposure (or included patients who had only limited exposure to cannabis-related products).

Eleven research papers examined cardiovascular outcomes, including stroke, myocardial infarction, cardiovascular mortality, and mortality from all causes. The only study that examined the use of marijuana as a potential trigger for myocardial infarction (heart attack) was a case-crossover study in 2001 that showed an increased risk for heart attack within the first hour after smoking marijuana. This study included 3,882 patients and was well designed, although it was subjected to potential confounding from recall bias.

Effects on heart rate

It is known that marijuana can increase heart rate and blood pressure, and may have ischaemia-inducing effects on vasculature (blood vessels), which may have harmful effects in some persons. We therefore need to increase our understanding of the health effects of marijuana. The researchers opined that it may have a medicinal role and help people, but that we also need to know what it does specifically to the cardiovascular system.

A prospective clinical trial (research going forward in time) that includes older patients with risk factors for cardiovascular disease, and that would track marijuana usage over a specific length of time, would help to improve our understanding of the matter. The reality is that marijuana (ganja) use is entrenched in most western societies, and so we need to have a better understanding of its effects on the human body.

Derrick Aarons MD, PhD is a consultant bioethicist/family physician, a specialist in ethical issues in medicine, the life sciences and research, and is the Ethicist at the Caribbean Public Health Agency – CARPHA. (The views expressed here are not written on behalf of CARPHA.)

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