title: Pulmonary function in cannabis users: Support for a clinical trial of the vaporizer.
abstract: BACKGROUND
  Debates about cannabis policy often mention respiratory symptoms as a negative consequence of use. The cannabis vaporizer, a machine that heats the plant to release cannabinoids in a mist without smoke and other respiratory irritants, appears to have the potential to minimize respiratory complaints.
  
  
  METHODS
  Twenty frequent cannabis users (uninterested in treatment) reporting at least two respiratory symptoms completed subjective ratings of respiratory symptoms and spirometry measures prior to and following 1 month's use of a cannabis vaporizer in a pre/post-design. Outcome measures included self-reported severity of nine respiratory symptoms as well as spirometry measures, including the maximum amount of air exhaled in 1s (forced expiratory volume; FEV1) and maximum total lung volume (forced vital capacity; FVC).
  
  
  RESULTS
  The 12 participants who did not develop a respiratory illness during the trial significantly improved respiratory symptoms (t(11)=6.22, p=0.000065, d=3.75) and FVC, t(11)=2.90, p=0.007, d=1.75. FEV1 improved but not significantly t(11)=1.77, p=0.053, d=1.07.
  
  
  CONCLUSIONS
  These preliminary data reveal meaningful improvements in respiratory function, suggesting that a randomized clinical trial of the cannabis vaporizer is warranted. The vaporizer has potential for the administration of medical cannabis and as a harm reduction technique.
authors.affiliation: Department of Psychology, University at Albany, SUNY, Albany, NY 12222, USA.
authors.forename: Nicholas T
authors.initials: NT
authors.lastname: Van Dam
authors.forename: Mitch
authors.initials: M
authors.lastname: Earleywine
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D002188:Cannabis / Q000737:chemistry*; D005260:Female; D005541:Forced Expiratory Volume; D040261:Harm Reduction; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000009:adverse effects*; D009330:Nebulizers and Vaporizers; D012140:Respiratory Tract Diseases / Q000139:chemically induced*; D012720:Severity of Illness Index; D013147:Spirometry; D014797:Vital Capacity; D055815:Young Adult