Wednesday, April 20, 2016

Adverse Health Effects Of Recreational Cannabis Use

Background: Cannabis plants produce a unique family of terpeno-phenolic compounds called cannabinoids, which produce the "high" one experiences from consuming marijuana. Cannabis is usually smoked in a ‘joint’ or with a water pipe (sometimes with tobacco added) because smoking is the most efficient way to achieve the desired psychoactive effects.

Two Major Constituents of Cannabis. THC is psychoactive.

A quick summary for all:
1. There are 483 identifiable chemical constituents known to exist in the cannabis plant, and at least 85 different cannabinoids have been isolated from the plant.
2. The two cannabinoids usually produced in greatest abundance are cannabidiol (CBD) and/or delta-9-tetrahydrocannabinol (THC), but only THC is psychoactive or gives “high”.
3. Since the early 1970s, Cannabis plants have been categorized by their chemical phenotype or "chemotype", based on the overall amount of THC produced, and on the ratio of THC to CBD. Although overall cannabinoid production is influenced by environmental factors, the THC/CBD ratio is genetically determined and remains fixed throughout the life of a plant.
4. Non-drug plants produce relatively low levels of THC and high levels of CBD, while drug plants produce high levels of THC and low levels of CBD. When plants of these two chemotypes cross-pollinate, the plants in the first filial (F1) generation have an intermediate chemotype and produce similar amounts of CBD and THC. Female plants of this chemotype may produce enough THC to be utilized for drug production.

Recreational Use:
Cannabis is used for a wide variety of purposes including recreational use, medical use and as hemp fibre. Many human culture including Chinese, Indian and Greek, etc., have records of cannabis use in various social and religious activities. Cannabis is a popular recreational drug around the world, only behind alcohol, caffeine and tobacco, and it is also available as baked product and as a tea!!!

Summary: The article reports analysis of various “side-effects” that have been associated with ‘heavy’ or ‘regular’ cannabis, which for the study purpose is defined as daily or near-daily use. Starting from year 1993 till year 2013, a comparison of the evidence in 1993 with the evidence and interpretation of the same health outcomes in 2013 is attempted. Various fallouts including health, social behaviors, education, etc. are evaluated for regular user vis-à-vis a non-regular/non-user.

Results: The key conclusions are:

Adverse Effects of Acute Cannabis Use
1. Cannabis does not produce fatal overdoses.
2. Driving while cannabis-intoxicated doubles the risk of a car crash; this risk increases substantially if users are also alcohol-intoxicated.
3. Cannabis use during pregnancy slightly reduces birth weight of the baby.

Adverse Effects of Chronic Cannabis Use
1. 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.
2. 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.
3. Regular adolescent cannabis users have lower educational attainment than non-using peers but researchers don't know whether the link is causal.
4. Regular adolescent cannabis users are more likely to use other illicit drugs, but researchers don't know whether the link is causal.
5. 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.
6. Regular cannabis use in adolescence approximately doubles the risk of being diagnosed with schizophrenia or reporting psychotic symptoms in adulthood.
7. Regular cannabis smokers have a higher risk of developing chronic bronchitis.
8. Cannabis smoking by middle aged adults probably increases the risk of myocardial infarction.

Article Citation: Hall, W. What has research over the past two decades revealed about the adverse health effects of recreational cannabis use? Addiction 2015, 110(1), 19-35. (free copy)