Speaking about the use of a controversial substance, such as marijuana, is impossible without making personal views and biases part of that conversation. I will try to separate, as best I can, personal views from data and medical guidelines. Like with any other euphorically psychoactive substance — substance that is able to produce pleasant mental effects (alcohol, tobacco, controlled prescription drugs and illicit drugs) there is a legitimate concern about addictions, which has not been, in my opinion, fully elucidated. At the same time, addictive potential does not guarantee that everyone develops an addiction and that there might not be circumstances under which a substance may be beneficial. To some extent the argument about euphorically psychoactive drugs is philosophical and bound to the values of a particular time and place.
As far as recreational use of marijuana, I wish to state the same concern we hear about other legal substances that produce pleasant mental effects, like cigarettes and alcohol. Such substances are not a good way of dealing with difficulties in life, and celebrations, if not well controlled, can turn harmful too. An occasional “party drug” can sometimes become either a gateway drug or an addiction in and of itself. Even if only a small number of users become addicted, it is difficult to say that such a drug is safe. There is also a question of how important personal mental freedom is to the person; if one needs to take something in order to feel well, one is less free than someone not needing to take a substance in order to feel well.
Medical marijuana has been used for various types of chronic pain and conditions that produce chronic nausea and disease induced weight loss. The use is palliative, not curative, meaning that it improves symptoms but does not improve the underlying condition that caused the symptoms. More recently the use of medical marijuana has expanded to be used in a wider spectrum of conditions, even for certain types of seizures and some cases of severe Autism, again to relieve symptoms, not to cure. A relief of symptoms can be an important quality of life measure in some situations. On the other hand, depending on the person’s preferred philosophy of life and the condition, it can take away the opportunities that dealing with any type of suffering can also offer.
As with any treatment, there are anecdotal cases of isolated remarkable successes with some health problems, which may be, at least to some extent, due to either a placebo effect or a true pharmacological effect. While medical marijuana can be beneficial for certain painful conditions for which there are no good alternatives, there are also risks. For example, some medical problems require making significant positive lifestyle changes such as smoking cessation, dietary changes, exercise. In those cases, marijuana can be inappropriately used if it becomes an unhealthy “shortcut,” a way of avoiding healthy but hard to do lifestyle changes.
At the same time, medical marijuana can certainly be helpful for some select conditions in persons with debilitated health and severe or poorly treatable medical problems, when making long lasting self-transformative lifestyle changes is not a realistic possibility, and suffering is too much to bear.
The risks are best described with the use of marijuana by teens and young adults. For example, a systematic review of studies from 1970s to 2006 found that nearly all studies report an association between use of cannabis and emotional problems (Lancet 2007; 370:319-28). Many other studies confirm this association indicating, for example, that those who use cannabis before age 17 were seven times more likely to attempt suicide (Lancet Psychiatry 2014; 4:286-93). The critics of these findings accurately point out that association is not causality and can simply mean that people with pre-existing emotional problems are more likely to self-medicate with cannabis.
It is impossible to resolve this uncertainty definitively by a controlled randomized, even if not blinded clinical trial, as such trials would not be ethical (it would not be ethical to randomize teenagers to groups of use and non-use of cannabis). At the same time it seems imprudent to ignore this data or to presume the hypothesis of non-harm to be true. If we are to be truly scientific we must concede that there is a genuine possibility of harm as there is also a possibility of non-harm, at least as far as the above mentioned emotional problems.
What complicates the issue even more is that teens tend to go with the “social flow.” An in-school survey of nearly a million adolescents exploring how social norms affect cannabis use, an annual survey 1976 to 2006, showed that the biggest predictor of cannabis use is related to social norms, more than any other factor, with marijuana use more than 3 times higher in cohorts with greater societal acceptance of marijuana use, regardless of their individual views (Addiction 2011;106(10):1790-800).
What we can learn from this is that in all likelihood, liberalizing cannabis use, whether we like it or not, will increase its use among teens. What can we do with this information? In medicine many substances that are both more addictive and more harmful than cannabis have been regulated for a long time, and I feel confident in the ability of medical professional guideline producing agencies to work out reasonable guidelines of its use. Outside of medical use, this rests in the hands of every individual with their elected political representatives.
1) Silins, E. et al. Young adult sequelae of adolescent cannabis use: an integrative analysis, The Lancet Psychiatry; September 2014; pp 286-293
2) Moore, T. et al. Cannabis use and risk of psychotic or affective mental health outcomes: a systematic review. The Lancet. Vol 370, No 9584 pp 319-328;
3) Katherine M. Keyes, PhD, John E. Schulenberg, PhD, Patrick M. O’Malley, PhD, Lloyd D. Johnston, PhD, Jerald G. Bachman, PhD, Guohua Li, MD, Deborah Hasin, PhD. The social norms of birth cohorts and adolescent marijuana use in the United States, 1976-2007. Addiction; 2011 Oct;106(10):1790-800.
Oleg is a board certified family physician, trained in New York. He subsequently worked in various practice settings, rural and urban, and on faculty at Oregon Health and Sciences University; authored a book and other publications; and currently is a physician for the employees and families of Jackson Laboratory — a genetic research facility in Maine. He is one of the contributors to Cancer: A personal challenge.