Surprising Facts About Marijuana – From Psychiatrist and Renowned Addiction Expert Herbert D. Kleber, MD
As part of Center on Addiction's Speaker Series, in which leading experts present their research and insights, Herbert D. Kleber, MD, Founder and Director Emeritus of the Division on Substance Abuse at the Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute, gave an in-depth presentation on marijuana and the effects of legalization. We spoke with Dr. Kleber to hear a little bit more about his take on marijuana legalization, edibles and how marijuana impacts the brain.
What is the impact of marijuana legalization in states like Colorado and Oregon?
Dr. Kleber: There have been many negative consequences as a result of legalization. I think a main takeaway would be that when marijuana is legalized, it becomes normalized and its accessibility increases for everyone, not just adults. There is a popular conception that marijuana is totally safe. But in Colorado and Oregon, we have seen rates of hospital admissions increase 81 percent from 2010 to 2015 due to marijuana-related causes. That’s a dramatic increase. In Washington, the percentage of Driving Under the Influence charges linked to marijuana doubled from about 18 percent in 2012 to 33 percent in 2015.
The impact of legalization on these states has been even wider reaching. Most people don’t know that 85 percent of drivers involved in fatal crashes in Washington tested positive for recent marijuana use. And in Colorado, marijuana poisoning cases among children has been rising an average of 34 percent each year compared to 19 percent in other states in the U.S.
Pro-marijuana groups also negate the impact the drugs will have on kids, but Colorado now leads the country in marijuana use among youth and Oregon is number five in the country. Research shows that marijuana use among youth can negatively affect the developing brain, so the fact that it’s becoming easier to access is worrisome.
We’ve heard a number of stories recently about unintentional overconsumption of edibles. How dangerous is this accidental consumption?
Dr. Kleber: It can be quite dangerous and debilitating. The problem with edibles is that the effects often take 30-60 minutes to kick-in and the duration of the effects can last up to eight hours. Many people will take an edible, hoping to feel “high” immediately and when they don’t feel anything, they take a larger amount. This can cause serious and overwhelming effects including: an increase in heart rate, dryness of the mouth, and/or feelings of paranoia or anxiety.
What are the chemical differences between smoked and oral marijuana use?
Dr. Kleber: When people smoke marijuana they experience a rapid onset of a “high” and major psychological effects take up to 30 minutes to develop. The peak plasma level (the time it takes for a drug to reach its highest concentration in the blood) occurs in 10 minutes. People are usually high for 2-3 hours depending on the dose.
In contrast, when people consume marijuana edibles, there is a greater percent of THC absorbed, but less predictable effects. The peak plasma level is 2-3 hours and the effects last much longer, up to 8 hours. The onset of “high” takes 30-60 minutes to develop.
Is marijuana safer than alcohol and tobacco?
Dr. Kleber: I’d like to answer this question with two quotes from Thomas McLellan, PhD, the co-founder and Chairman of the Board of the Treatment Research Institute, a non-profit research and development institute in Philadelphia.
“I guess the argument of legalizing marijuana that baffles me the most is the one I actually most agree with: It’s not worse than alcohol. I think that is really pretty accurate. So how has making alcohol more available worked out for us?”
“Let’s see; What I read is that American students are lagging in math, science and general education. Wait – I know, we’ll make marijuana more available – that ought to fix things.”
Herbert D. Kleber, MD
Dr. Kleber is Founder and Director Emeritus of the
Division on Substance Abuse at the Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute