A recent study by the Canadian government found cannabis contained more toxic substances than tobacco smoke.[47] The study determined that marijuana smoke contained 20 times more ammonia, and five times more hydrogen cyanide and nitrous oxides than tobacco smoke. In spite of this, a recent large-scale study found no correlation between heavy marijuana use and lung cancer, despite noting that cannabis contains the same carcinogens as tobacco. The same study found a 20-fold increase in lung-cancer rates of smokers who consumed two or more packs of cigarettes per day.[48] These researchers postulated that the THC present may have a "protective effect" by causing aging cells to die before they become cancerous.[49] Other recent research suggest the cannabinoid CBD may stop certain cancers from spreading, although not in concentrations consumed during smoking.[50]
In contrast, a study published in the January 2008 edition of the journal Respirology found that "regular" cannabis smokers who developed bullous lung disease[[2]] did so on average 24 years sooner than tobacco smoking counterparts.[51] Researchers attributed this to the inhalation of a larger volume of smoke, and typically holding it for four times longer than tobacco smokers. Bullous lung disease is considered an uncommon cause of respiratory distress.[52] In general, habitual inhalation of any kind of smoke is detrimental to lung health.[53]
Cannabis use has been linked to exacerbating the effects of depression, psychosis, schizophrenia, bronchitis, and emphysema by several peer-reviewed studies for those who are vulnerable to such illnesses based on personal or family history.[54] More recently, the Dunedin Multidisciplinary Health and Development Study published research showing an increased risk of psychosis for cannabis users with a certain genetic predisposition, held by 25% of the population.[55] Studies have also shown links between heavy long-term use (over five joints daily over several years) and incidence of heart attacks, strokes, as well as abnormalities in the amygdala and hippocampus regions of the brain.[56][57]
In July 2007, British medical journal The Lancet published a study that indicates that cannabis users have, on average, a 41% greater risk of developing psychosis than non-users. The risk was most pronounced in cases with an existing risk of psychotic disorder, and was said to grow up to 200% for the most-frequent users.[58][59][60]
WIKIPEDIA BITCH
Oh yeah,
http://en.wikipedia.org/wiki/Health_issues_and_the_effects_of_cannabis
