No smoke, no fire: What the initial literature suggests regarding vapourized cannabis and respiratory risk

Habits and Lifestyles Laboratory, Department of Psychology, University at Albany, State University of New York, Albany, New York, USA Correspondence: Dr Mitch Earleywine, University at Albany, 1400 Washington Avenue, Albany, New York 12222, USA. Telephone 518-442-4836, e-mail [email protected] As more municipalities relax restrictions on access to cannabis, questions about the plant’s potential for respiratory effects become more common. Given current limitations in developing an inhalant alternative for delivering cannabis medication, smoked marijuana remains the most readily accessible form of cannabis among medicinal users (1). An important question that remains is how to improve safety for the respiratory system in individuals who choose to use cannabis medicinally. Although frequent comparisons with tobacco emphasize that the smoke from cannabis has more carcinogens and respiratory irritants, the absence of nicotine likely mitigates the impact of some of these compounds (2). Evidence suggesting a link between cannabis and lung cancer is equivocal (2-4), but other concerns remain important. Frequent smokers of cannabis often report respiratory problems. Many users experience symptoms of bronchitis including coughing, wheezing and tightness in the chest (5,6). Informed health care professionals may consider making recommendations to their medicinal cannabis patients for vapourization of the plant, particularly for those who want the rapid relief that oral administration fails to provide. It is not our intention to encourage inappropriate use of the plant, but to increase safety for those who choose to use it. Vapourization of cannabis is likely less harmful than smoking. Nevertheless, researchers have yet to gather some of the most necessary data regarding the topic. There have been no published randomized clinical trials investigating vapourization with long-term follow-up; therefore, drawing firm conclusions about the impact of the technique is difficult. Preliminary findings do support the idea that vapourization is an improvement over smoking.