Ooh, looky here! Some Aussie cannabis activists have unearthed an interesting study from 2006! Check this shizz out:
Active component of marijuana and Alzheimer’s disease pathology (Hereafter: Eubanks, et al. 2006.)
Yeah, umm, the most excitable of the pro-pot people are jumping on this study as indispootaple proof that cannabis cures/treats/manages Alzheimer’s disease.
Now, I’m for the legalisation of marijuana; but I happen to think that propaganda is self-defeating and destructive, so I’m very much against enabling propagandists who otherwise agree with me on certain issues. That means that sometimes, correction is called for.
Alzheimer’s disease is a currently incurable affliction that slowly kills neurons in many parts of the brain. The first brain structure that Alzheimer’s attacks is the hippocampus, which is where memories are encoded, and this is why most people associate the condition with the dramatic memory loss.
Alzheimer’s presents with catastrophic cell death (obviously) and higher-than-normal levels of amyloid plaque deposits in certain regions of the brain. In healthy people, the death of neurons and the presence of large deposits of amyloid plaque is often a consequence of ageing, but in Alzheimer’s, these harrowing symptoms occur much more rapidly and extensively.
(Click here for a refresher on neurons.)
The study found that pot seems to inhibit the activity of an enzyme called acetylcholinesterase (AChE) in the brain. AChE breaks down unused acetylcholine at the synapse (the inconceivably tiny space between the axon terminal of one neuron and the receptors of another). Acetylcholine is an extremely important neurotransmitter (a chemical signal that affects the polarisation of the receiving neuron, which either provokes or inhibits an action potential); but like anything good, you don’t want too much of it; you need a balance. That’s where AChE comes in.
When AChE activity goes a bit overboard (often due to genetics), excessive accumulations of amyloid plaque start to develop in the brain. This process is called AChE-induced amyloid beta-peptide aggregation. When amyloid beta-peptides a synthesised in healthy brains, they protect against oxidative stress, help regulate cholesterol transport and do other non-threatening thngs; but once again, too much of a good thing can be bad news. Large deposits of these peptides can also result in inflammation, and as above, a brain afflicted by Alzheimer’s is riddled with them.
But correlation does not imply causation. According to the amyloid hypothesis, Alzheimer’s disease is caused by this build-up of brain plaque. This hypothesis doesn’t really hold, though, because a vaccine that clears amyloid plaques was developed and trialed. During stage I trials, it was found that the clearing of amyloid plaque did not have a significant effect on the onset of dementia.
Thus, the thing that cannabis does especially well will reduce the development of a neurological marker of Alzheimer’s disease. Clearly Alzheimer’s is related to amyloid plaques, but we still aren’t sure how. So it would be premature to suggest that this function of cannabis could play a part in the treatment of Alzheimer’s disease.
As I said above, AChE inhibition does mean that more acetylcholine will be present in the synaptic gap during neurotransmission. A little extra acetylcholine is associated with boosts in cognition; so the inhibition of AChE is one way to boost cognition. There are already drugs on the market, and such drugs (like Exelon) are often used to slow the progress of Alzheimer’s disease. So could pot do that too?
Well, no. Cannabis is quite different.
Acute intoxication with cannabis comes with a disruption of short-term memory for as long as the high lasts. This effect is due to the inhibition of the release of neurotransmitters, including acetylcholine, in the hippocampus. In fact, researchers have remarked that the extent of neural inhibition in the hippocampus for the length of the high actually resembles a temporary hippocampal lesion.
The consumption of too much pot over the long term does make you stupid. Worse, doses of marijuana to equal doses of similar drugs used in Alzheimer’s treatments would lead to THC-induced hippocampal deterioration, which is what Alzheimer’s disease does on its own. Moreover, if you read Eubanks, et al. with a fairly comprehensive dosage chart handy, it’s clear that you would have to consume a heavy dose of THC in one session to achieve a substantial inhibition of AChE enzymes. No, that’s not a challenge.
So the cannabis you smoke actually won’t do shit for Alzheimer’s patients. It’s kinda like pouring a little bit of gasoline on a house fire.
But targeted drugs derived from cannabis might. Even so, the work of Eubanks, et al. offers no argument in favour of legalising cannabis. To claim it does is simply misleading.
So can we stop pretending that cannabis is some kind of magical wonder drug suppressed by Big Pharma? It’s not. It’s just a relatively safe recreational drug with some notable medicinal uses. That should be our platform.
Now, don’t get me wrong: if you live in my state, join that group and support them. (It should go without saying, but: you don’t have to be a pothead to support legalisation. I’m not a user, I just happen to believe that proscribing a victimless source of pleasure while tolerating more destructive sources of pleasure is simply wrong.)