To be clear up front, I have never used it, nor would I unless 1) it is legalized in my jurisdiction; and 2) I have a valid medical need and prescription. That doesn't mean I am supportive of unwarranted recreational use. But I don’t believe it should be illegal. By that, I mean I am principally against big government. And my opposition to big government means I don’t think they should be nearly as pervasively or extensively involved in the non-violent affairs of the citizenry as they are. Just as an adult has the legal right to smoke tobacco, I believe they should have the legal right to smoke marijuana.
Now for a short history lesson. Cannabis being listed as a Schedule 1 controlled substance in the first place stands on rather shaky ground. It has had significant use and acceptance throughout history, and among many cultures. Of course that’s no proof of safety, but it certainly helps to give some insight into whether it’s really as dangerous as propagandists make it out to be. In general, though, the negative connotations are a relatively recent invention.
It started after the Mexican Revolution in the early 1900s. As the demonization of Mexicans became a big thing, the government enacted marijuana tax laws to give themselves an excuse to search, detain, and deport Mexican immigrants. This method of control turned out to be very successful. The Marijuana Tax Act of 1937 was eventually ruled unconstitutional and illegal, but was quickly replaced by the Controlled Substances Act in 1970. As the bill was being drafted in a House committee, Assistant Secretary of Health Roger O. Egeberg suggested that cannabis be placed in the most restrictive category, Schedule 1, supposedly as a placeholder while President Nixon commissioned a report. In 1972, Raymond P. Shafer presented that report to Congress, declaring that marijuana should not be in Schedule 1 and even doubted its designation as an illicit substance. However, President Nixon discounted the recommendations of the commission, and marijuana remains a Schedule 1 substance today.
Being a Schedule 1 controlled substance has put a major hamper on research. Being illegal to grow, import, or possess, United States scientists really can't learn more about it. And if a scientist were to study it privately, they couldn't publish their findings for fear of years of imprisonment. Luckily, recent law changes in select states and legality in other countries has allowed continued research. What good research is available supports there being valid medicinal properties.
Smoking pot does, indeed, come with harmful consequences, which shouldn't be ignored. However, most of those are related to the carcinogenic tars, such as nitrosamines, reactive aldehydes, and polycyclic hydrocarbons, as well as carbon monoxide produced by burning carbon-based plant materials. Additionally, build-up of unburned plant matter and excess exposure to heat for the lungs can have negative repercussions. But most, if not all of those negatives can be mitigated by extracting the cannabinoids from the plant material, as in hash oil or edibles. There are also potentially negative consequences for brain development, but they are minimal, and often avoidable. As per the Medical Cannabis page on Wikipedia: "Effects of chronic use may include... subtle impairments of attention and memory. These deficits persist while chronically intoxicated. There is little evidence that cognitive impairments persist in adult abstinent cannabis users. Compared to non-smokers, people who smoked cannabis regularly in adolescence exhibit reduced connectivity in specific brain regions associated with memory, learning, alertness, and executive function. A study has suggested that sustained heavy, daily, adolescent onset cannabis use over decades is associated with a decline in IQ by age 38. No effects were found in those who initiated cannabis use later, or in those who ceased use earlier in adulthood." Aside from the potential, rather minor negative effects, using cannabinoid extracts can have a wide spectrum of valid medical uses. Cannabidiol(CBD), for example, has notable neuroprotective and anxiolytic effects. However, abuse and addiction are still important to watch out for, given the mildly addictive and psychoactive side-effects of tetrahydrocannabinol(THC).
Considering smoked cannabis is not too different in negative consequences to smoked tobacco (and any other smoked plant material), but also considering means of mitigation and valid medicinal uses, I fully support its legalization for medical use at the least, especially in light of the racist and propagandized basis for it being made illegal in the first place.
Citations and further reading:
[1] https://en.wikipedia.org/wiki/Marihuana_Tax_Act_of_1937
[2] https://en.wikipedia.org/wiki/National_Commission_on_Marihuana_and_Drug_Abuse
[3] http://www.drugpolicy.org/blog/how-did-marijuana-become-illegal-first-place
[4] https://en.wikipedia.org/wiki/Medical_cannabis
[5] https://en.wikipedia.org/wiki/Effects_of_cannabis
