Yet for more than three decades the scientific study of these anti-cancer effects has remained almost exclusively limited to preclinical in vitro (in a petri dish) and in vivo (in lab animals) analysis, rather than clinical (human) study. Why? A just published review in the Journal of Pharmacy and Pharmacology provides an answer.

Cannabinoid receptor ligands as potential anticancer agents – high hopes for new therapies?
abstract excerpt via PubMed

In recent years, CB receptor ligands, including Delta(9)-tetrahydrocannabinol, have been proposed as potential anticancer agents. This review critically discusses the pharmacology of CB receptor activation as a novel therapeutic anticancer strategy in terms of ligand selectivity, tissue specificity and potency. Intriguingly, antitumour effects mediated by cannabinoids are not confined to inhibition of cancer cell proliferation; cannabinoids also reduce angiogenesis, cell migration and metastasis, inhibit carcinogenesis and attenuate inflammatory processes.

Sounds promising, huh? Well it is — that is, until you get to this:

The development of CB(2)-selective anticancer agents could be advantageous in light of the unwanted central effects exerted by CB(1) receptor ligands.

And just what are these terrible “unwanted effects” — effects so “problematic” that we must continue to forbid scientists from clinically studying the drug’s effects in cancer patients? I’ll let the authors explain.

“In terms of a potential therapeutic application the unwanted psychotropic effects mediated via CB1 could be a problem.”

You read that right. The ‘problem’ with cannabinoids anti-cancer abilities is that patients might temporarily feel better after they take them!

Now contrast mainstream science’s feigned concern with the so-called ‘unwanted effects’ of the natural cannabis ‘high’ with the actual side-effects of the pharmaceutical cannabinoid antagonist drug rimonabant (aka Acomplia), which was recently withdrawn from the European market because of the the drug’s link to depression and suicide.

The psychiatric side-effects of rimonabant

Experimental evidence has suggested that drugs that enhance cannabinoid type-1 (CB1) receptor activity may induce anxiolytic and antidepressant effects, whilst the opposite has been reported with antagonists. Thus, the objective of the present review is to discuss the potential psychiatric side-effects of CB1 receptor antagonists, such as rimonabant, which has been recently marketed in several countries for the treatment of smoking cessation, obesity and associated metabolic disorders.

… Patients taking CB1 receptor antagonists should be carefully investigated for psychiatric side-effects. These drugs should not be prescribed for those already suffering from mental disorders. Nevertheless, the development of new compounds targeting the endocannabinoid system for the treatment of several conditions would be necessary and opportune.

Let’s review shall we? Natural plant selectively kills cancer, but it may also get you high = “problematic.” Synthetic pharmaceutical drug short circuits the body’s natural endocannabinoid system and will likely make you depressed and suicidal = “opportune.”

Any questions?

I’ve said this before but it bears repeating. The endocannabinoid system is involved in the regulation of a broad range of primary biological functions in humans — including appetite, mood regulation, blood pressure, bone density, reproduction, learning capacity, and motor coordination.

Shutting down this system in order to lose a few vanity pounds is likely not a good idea — and, in fact, is a pretty effective way to kill mice.

It’s arguably not a healthy option for humans either.

UK drug body: Sanofi’s Acomplia linked to five deaths
via CNN

Sanofi-Aventis S.A.’s (SNY) anti-obesity pill Acomplia has been linked to five deaths and 720 adverse reaction since its U.K. launch in 2006, according to a document posted on the U.K. drug regulator’s website Tuesday.

One of the deaths was due to suicide, said the Medicines and Healthcare products Regulatory Agency, or MHRA, document, which recorded adverse side effects up until May 9.

The drug, a new kind of obesity treatment that blocks certain brain receptors that regulate appetite, last year was rejected by a panel of U.S. Food and Drug Administration experts on concerns that the drug increases the number of psychiatric events like depression and suicidal thinking among users.

… Despite withdrawing its application to market the drug in the U.S., where it was to have been known as Zimulti, Sanofi-Aventis has plans to resubmit it to the FDA and other regulators in 2009 for approval as a treatment for type 2 diabetes.

In a study released in 2006, Acomplia showed promise as a diabetes treatment after patients who took the pill for a year reported improvements in blood sugar control and cholesterol along with modest weight loss.

However, a recent study of the drug in obese heart patients found more than 40% of those who took the drug developed psychiatric problems, while another study, published last month, raised concerns about using drugs like Acomplia in children.