Cannabis is the most widely smoked illicit substance in the world. It can be smoked alone in its plant form, marijuana, but it can also be mixed with tobacco. The specific effects of smoking cannabis are difficult to assess accurately and to distinguish from the effects of tobacco; however its use may produce severe consequences. Cannabis smoke affects the lungs similarly to tobacco smoke, causing symptoms such as increased cough, sputum, and hyperinflation. It can also cause serious lung diseases with increasing years of use. Cannabis can weaken the immune system, leading to pneumonia. Smoking cannabis has been further linked with symptoms of chronic bronchitis. Heavy use of cannabis on its own can cause airway obstruction. Based on immuno-histopathological and epidemiological evidence, smoking cannabis poses a potential risk for developing lung cancer. At present, however, the association between smoking cannabis and the development of lung cancer is not decisive.
Keywords: Cannabinoids; Cannabis; Lung diseases; Marijuana; Respiratory health; Respiratory risk.