Family Commentary

Introduction – Fourteen percent of Canadians reported abusing cannabis (marijuana) in 2003, according to a 2004 Canadian Centre on Substance Abuse (CCSA) study. The study showed 30% of 15-17 year olds and 47% of 18-19 year olds were abusers.

?The rise in cannabis use, especially among young Canadians, is of concern because we know that cannabis is not a benign substance. There are a number of health risks associated with use and these risks increase with a lower age of initiation and more frequent use.? – CCSA CEO Michel Perron.

Heart ? A recent study indicates an abuser?s heart attack risk increases by a factor of four in the first hour after smoking cannabis. Such an effect may occur due to cannabis? effects on blood pressure, heart rate and a reduction in the oxygen-carrying capacity of the blood. Mittleman MA, Lewis RA, Maclure M, et al: Triggering myocardial infarction by marijuana. Circulation 103:2805-2809, 2001.

Lungs – Abusers who smoke cannabis frequently have greater health problems and use more sick days than nonsmokers. Respiratory illnesses were common among the cannabis smokers. Polen MR, Sidney S, Tekawa IS, et al: Health care use by frequent marijuana smokers who do not smoke tobacco. West J Med 158:596-601, 1993.

Immune system suppression ? THC, the psycho-active ingredient in cannabis, appears to impair the immune system?s ability to fight off cancer and various infectious diseases. In laboratory experiments that exposed animal and human cells to THC, the normal disease-preventing reactions of many of the key types of immune cells were inhibited. Adams IB, Martin BR: Cannabis: pharmacology and toxicology in animals and humans. Addiction 91:1585-1614, 1996.

Pregnancy – Smoking cannabis during pregnancy harms unborn children. Babies are smaller, and in childhood, their cognitive functioning shows impairment up to the age of six. Day NL et al. Neurotoxm Teratol 1994. Fried PA: Archives of Toxicology 1995 (suppl) 17: 233-60.

Addiction – Drug craving and withdrawal symptoms were reported by long-term cannabis abusers attempting to cease using the drug. Kouri EM, Pope HG, Lukas SE: Changes in aggressive behavior during withdrawal from long-term marijuana use. Psychopharmacology 143:302-308, 1999.

Impairment – A study of 6,000 Canadian teenagers found that drivers who had smoked cannabis were four times more likely to be involved in an accident than non-abusers. Asbridge, M., Poulin, C., and A. Donato: ?Driving under the influence of cannabis and motor vehicle collision risk: evidence from adolescents in Atlantic Canada?, Accident Analysis and Prevention, 2005

Mental Health – Cannabis abuse increases the risk of developing mental illnesses including schizophrenia, psychosis, depression, suicidal behaviour and anxiety. Significant cannabis abuse severely increased the risk of psychosis. Arsenault L et al: Arch Gen Psychiatry, vol 57 Oct. 2000 and Zammit S et al.: British Med Journal 2002; 325, 1195ff.

Social problems