Herbert D. Kleber, MD

What are we talking about when we discuss medical marijuana? What about legalizing 

? What is the potency, purity, and so on? What about regulation? Here to discuss is Dr Herbert Kleber, Professor of Psychiatry and Director of the Division on Substance Abuse at the Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute in New York.

According to Dr Kleber and other experts in 

, in the days of John Lennon-who referred to marijuana as a "harmless giggle"-its potency was approximately 2% (THC). Today, it is between 10% and 30%. It is a very different drug, a potent drug, but the potency of any given "batch" is not known to the consumer. One must take the distributor's word for it on the quality and effectiveness of the product.

There is increasing evidence that individuals who try marijuana during their early 

 are affected neurologically for a decade or more at least until one's 20s and perhaps even longer.

Operating a motor vehicle or machinery while under the influence of marijuana is a concern. We need better ways of measuring how much THC is in the bloodstream and what effect it has on driving, or whether it was used yesterday or two hours ago. There seems to be some suggestion that more recent the marijuana use, the riskier it is to drive.

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There is increasing evidence that individuals who try marijuana during their early teenage years are affected neurologically for a decade or more at least until one's 20s and perhaps even longer. More in this video.

Author | Herbert D. Kleber, MD

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