CME: Cannabis and the lung

The use of cannabis is embedded within many societies, mostly used by the young and widely perceived to be safe. Increasing concern regarding the potential  for  cannabis  to  cause  mental  health  effects  has  dominated  cannabis research  and  the  potential  adverse  respiratory  effects  have  received  relatively little attention. Studies on cannabis are challenging and subject to confounding by concomitant  use  of  tobacco  and  other  social  factors,  and  while  many  of  the studies  referred  to  in  this  review  are  beset  by  the  difficulties  inherent  in undertaking  epidemiological  research  of  the  effects  of  cannabis,  there  is  an emerging concern among many chest physicians who would suggest that habitual smoking of cannabis may contribute to the development of chronic obstructive pulmonary   disease,   pneumothorax   and   respiratory   infections,   including tuberculosis.  Special  attention  should  be  given  to  the  risk  of  lung  cancer, particularly as biological plausibility may precede epidemiology.