Substance abuse clarifications
The authors respond
Dr. Gorelick’s detailed comments brought up many points, which we address below.
Marijuana and cancer—Dr. Gorelick commented that the article “grossly exaggerated the cancer risk from marijuana smoking” due to the cited reference stating that the evidence is “limited and inconsistent.” We agree the article mentions the evidence is not clear. However, in further reading of their discussion of the risk of lung cancer the authors point to several epidemiologic studies, some of which showed increased risk of cancer. Specifically, a study from the United States showed “a history of daily or near-daily marijuana smoking was associated with a 2.6-fold greater risk for developing head and neck cancer.”
In our article we focused more on the positive results than on the entire picture and would have served our readers better by not making such an equivocal statement about the increased risk of cancer.
Marijuana and AF—Dr. Gorelick questioned the tenacity of the association between marijuana and AF, stating “given the ratio between 6 published cases reports and the millions of people smoking marijuana daily, this may be a more appropriate perspective for a review article.”
Our comments were based on the following statements from the cited study: “During the past few years an increasing number of case reports indicate an association between marijuana smoking and the development of AF.” Also, “despite the small number of these reports, the observed close temporal relationship between marijuana smoking and AF occurrence, especially in young people without structural heart disease or other precipitating factors for AF, strongly supports an association between the two conditions.”
We mentioned AF because this is not something most people consider as a side effect of marijuana and we felt it was useful to call attention to it as a potential complication. However, we do agree that the sentence could have been worded differently because the number of cases remains low and the risk of developing AF in young healthy adults is low.
Marijuana and cognitive effects—Dr. Gorelick commented that there is “no scientific basis for the statement in the article” and that the article cited looked only at 28 days post-cannabis use. The following comments were made in the article we cited: “However, one electroencephalographic study suggested greater abnormalities in longer term cannabis users, and another found a strong correlation between performance on a selective attention task and duration of cannabis use, even in users abstinent for a mean of 2 years.”
Also, that article concluded “…an opposite impression emerges from a recent large, carefully controlled study by Solowij et al, who found that longer term cannabis users showed significantly greater deficits on several neuropsychological measures than shorter term users, and that these measures were often negatively correlated with lifetime duration of use.”
Again, we agree that our comment was likely too broad because the evidence is limited and not clear, which is why we wrote, “However, most studies suggest that marijuana-associated cognitive deficits are reversible and related to recent exposure.”
Cocaine and cardiac complications—We thank Dr. Gorelick for providing additional information and resources about the very important association between cocaine use and the MI risk. We certainly agree that the inclusion of his suggested references would have been appropriate.
Raheel Khan, DO
Assistant Clinical Professor
Psychosomatic Medicine
Department of Psychiatry and Behavioral Sciences
Robert M. McCarron, DO
Training Director, Internal Medicine/Psychiatry Residency
Department of Psychiatry and Behavioral Sciences
Department of Internal Medicine
University of California, Davis
Sacramento, CA
