Key Findings From A 20 Year Study Into The Effects Of Using Marijuana
Adverse effects of acute cannabis use
- Cannabis does not produce fatal overdoses.
- Driving while cannabis-intoxicated doubles the risk of a car crash; this risk increases substantially if users are also alcohol-intoxicated.
- Cannabis use during pregnancy slightly reduces birth weight of the baby.
Adverse effects of chronic cannabis use
- Regular cannabis users can develop a dependence syndrome, the risks of which are around 1 in 10 of all cannabis users and 1 in 6 among those who start in adolescence.
- Regular cannabis users double their risks of experiencing psychotic symptoms and disorders, especially if they have a personal or family history of psychotic disorders, and if they start using cannabis in their mid-teens.
- Regular adolescent cannabis users have lower educational attainment than non-using peers but we don’t know whether the link is causal.
- Regular adolescent cannabis users are more likely to use other illicit drugs, but we don’t know whether the link is causal.
- Regular cannabis use that begins in adolescence and continues throughout young adulthood appears to produce intellectual impairment, but the mechanism and reversibility of the impairment is unclear.
- Regular cannabis use in adolescence approximately doubles the risk of being diagnosed with schizophrenia or reporting psychotic symptoms in adulthood.
- Regular cannabis smokers have a higher risk of developing chronic bronchitis.
- Cannabis smoking by middle aged adults probably increases the risk of myocardial infarction.
Professor Wayne Hall has made large contribution in the field of public health in the area of drug use, addiction, treatment, ethics, and research as World Health Organization’s expert adviser. As a “Highly Cited Author” identified by the Institute for Scientific Analysis, he is dedicated to public health research. He is currently working as a NHMRC Australia Fellow on addiction neuroethics (see www.addiction-neuroethics.com) and his research interests include alcohol and drug research and education, cancer prevention, epidemiology, health policy, mental health, pharmacoeconomics and policy, and tobacco control.