August 4, 2010 – Before deciding that this plant should be legal to smoke, consider the effect on public health, a Stanford expert warns.

You may support California’s Proposition 19, the Regulate, Control and Tax Cannabis Act of 2010, because you think the war on drugs unfairly targets minorities. You may be in favor of it because you think it’s up to you, not the government, to decide what substances you’d like to consume as long as you don’t harm others. Or you may be sympathetic to the ballot measure based on the testimonials of patients with cancer or AIDS who swear that medical marijuana helps them cope with their illness.

But if pot is made legal, what would that mean for public health in the Golden State? Nothing good, says Keith Humphreys, a professor of psychiatry and behavioral medicine at the Stanford School of Medicine.

Humphreys, a clinical psychologist who recently spent a year in the Obama administration’s Office of National Drug Control Policy as a senior policy advisor, says the health effects of Proposition 19 are being overlooked by the 52% of Californians who supported the measure in a recent poll. In a podcast available on the Stanford website, he says his No. 1 fear is that it would create a lucrative product line for tobacco companies or create an industry that would stand “shoulder to shoulder with them lobbying against every anti-smoking restriction and expansion of public health and every taxation initiative.”

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Cigarettes still kill 400,000 people each year despite decades of regulation and anti-smoking campaigns, Humphreys said. But there’s reason to fear that Proposition 19 could make things worse. In European countries like the Netherlands, tobacco and marijuana are often smoked together and the combination is “both more addictive and more cancer-producing than either of those separately,” he said.

Humphreys said he has no doubt that marijuana has legitimate medical uses, and compounds within the plant will probably be turned into “maybe half a dozen decent medications” to alleviate pain, improve appetite and treat muscle spasms for patients with multiple sclerosis. But that doesn’t mean consumption of the entire plant — which contains more than 200 chemicals — is either beneficial or safe, especially when smoked, he said.

“Cocaine has medical uses,” especially as an anesthetic, Humphreys said, but that doesn’t mean it “should be available at 7-Eleven.”

You can download the complete podcast here.

By Karen Kaplan. Source.

July 21, 2010 – Can smoking marijuana prevent the memory loss associated with normal aging or Alzheimer’s disease? This is a question that I have been investigating for the past few years. The concept of medical marijuana is not a new one. A Chinese pharmacy book, written about 2737 BCE, was probably the first to mention its use as a medicine for the treatment of gout, rheumatism, malaria, constipation, and (ironically) absent-mindedness.

So what does marijuana do in the brain? It produces some excitatory behavioral changes, including euphoria, but it is not generally regarded as a stimulant. It can also produce some sedative effects but not to the extent of a barbiturate or alcohol. It produces mild analgesic effects (pain relief) as well, but this action is not related pharmacologically to the pain-relieving effects of opiates or aspirin.

Finally, marijuana produces hallucinations at high doses, but its structure does not resemble LSD or any other hallucinogen. Thus, marijuana’s effects on our body and brain are complex. Just how does it achieve these effects and are they beneficial? The chemicals contained within the marijuana plant cross the blood-brain barrier and bind to a receptor for the brain’s very own endogenous marijuana neurotransmitter system. If this were not true, then the marijuana plant would be popular only for its use in making rope, paper, and cloth.

The first endogenous marijuana compound found in the brain was called anandamide, from the Sanskrit word ananda meaning “bliss.” Anandamide interacts with specific receptor proteins to affect brain function. The great abundance of these receptors gives an indication of importance of the endogenous system in the regulation of the brain’s normal functioning. Recent investigations have also shown that stimulating the brain’s marijuana receptors may offer protection from the consequences of stroke, chronic pain, and neuroinflammation.

Surprisingly, it may also protect against some aspects of age-associated memory loss. Ordinarily, we do not view marijuana as being good for our brain and certainly not for making memories. How could a drug that clearly impairs memory while people are under its sway protect their brains from the consequences of aging? The answer likely has everything to do with the way that young and old brains function and a series of age-related changes in brain chemistry. When we are young, stimulating the brain’s marijuana receptors interfere with making memories. However, later in life, the brain gradually displays increasing evidence of inflammation and a dramatic decline in the production of new neurons, called neurogenesis, that are important for making new memories.

Research in my laboratory has demonstrated that stimulating the brain’s marijuana receptors may offer protection by reducing brain inflammation and by restoring neurogenesis. Thus, later in life, marijuana might actually help your brain, rather than harm it. It takes very little marijuana to produce benefits in the older brain; my colleague in France, Dr. Yannick Marchalant, coined the motto “a puff is enough” because it appears as though only a single puff each day is necessary to produce significant benefit. The challenge for pharmacologists in the future will be to isolate the beneficial effects of the marijuana plant from its psychoactive effects. Source.