Thanks for sharing, here are some thoughts.
I thought the potential health benefits of cannabis were a little under-represented in the article. There have been some rather remarkable stories regarding cannabis use for seizures, most of the evidence I have seen is anecdotal, however. I like that the article pointed out that cannabis could end up having legitimate medicinal benefits, but that most money has gone into researching the harmful effects of the drug. I myself am skeptical that cannabis is a wonder-drug, even for seizures, since the people who have used it successfully have not done so over many years. Its medicinal benefits in terms of pain management are incontrovertible, but other drugs are effective at managing pain too.
The article spent a lot of time addressing the harmful consequences of cannabis use, of which there were basically:
i) short-term effects: "it impairs memory and coordination, and can cause paranoia and psychosis"
ii) long-term effects: "Around 9% of users become dependent on the drug." Evidence that cannabis use leads to lung cancer is equivocal: "A 2008 study in New Zealand found that smoking pot increased the risk of lung cancer by 8% for each 'joint-year' (the equivalent of smoking a joint per day for one year), even after taking tobacco use into account. But other studies have found little to no correlation with lung cancer, even for heavy users."
iii) developmental effect on growing brains: "Some researchers have found links to poor educational performance, low social attainment — such as job status — and altered brain development. For example, the Christchurch Health and Development Study — which followed almost 1,300 children born in New Zealand in 1977 — found that people who used cannabis daily are around 50% more likely to have psychotic symptoms than are non-users and are at greater risk of not finishing school." "...persistent cannabis use, especially if started young, correlates with steeper declines in IQ in later life and with problems with memory and reasoning compared with people who have never used the drug."
As the article also acknowledged, however, there simply is not enough data to draw any causal links, especially with respect to ii) and iii): "For example, adolescents who use cannabis are probably also drinking excessive amounts of alcohol and engaging in other risky activities. Attributing the effects to one particular substance or behaviour is therefore very difficult."
It seems the only UNCONTROVERSIAL effects of marijuana are its short-term effects. Anyone who has used the drug can attest to these, even psychosis, at least according to its psychological definition (being disconnected from reality, which may involve hallucinations or delusions). I've been there! (Though, I think it was the bad veggie burgers I ate, which were soaking in some water at the bottom of a cooler for hours, and not the pot, as I've never experienced it since).
When it comes to the long-term effects of cannabis use, one might raise a number of questions. For example, how does the 9% dependence rate compare to alcohol, tobacco, and prescription meds? If it's much lower, then it's not really a mark against the drug. Who is going to give cannabis to children except in extremely rare circumstances (e.g., seizures)? Again, if you're the sort of parent who wouldn't let your child smoke tobacco or drink alcohol, these findings are not a mark against the drug. That said, I do worry that persistent and prolonged cannabis use, even on developed, adult brains, may have similar effects. If some study showed that it led to a lower IQ among adults, that would give me pause because I need my brain operating optimally in my line of work.
As I've stated previously, I welcome additional studies on cannabis use, and not because I think all of them will vindicate the drug. I am a "medicinal" user myself (I have a prescription but I use that term loosely). There is little question in my experience, at least to date, that cannabis has improved my quality of life and my spouse's. It is not addictive, I have never experienced withdrawals (went to Canada for 8 days earlier this year, no pot, no problem), and it helps me sleep and unwind. That said, some nights I don't want to eat the entire kitchen and sometimes, rather than helping me forget work, certain strains will make worry about it more. So I am still trying to find a balance with using it myself.
