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On the Record with Dr. Staci Gruber

An exclusive interview with one of the country’s leading marijuana researchers

May 1, 2015 Print

With recent appearances on the CNN documentaries Weed and Weed 3, McLean’s Staci Gruber, PhD, has been thrust into the center of the nation’s ongoing debate regarding the legalization of recreational marijuana and the use of medical marijuana. For Gruber, who always prefers to see patients rather than sit down for an interview, this attention is a necessary burden in order to help drive the conversation and inform the public and policymakers about the science of pot.

On a recent Friday afternoon, Dr. Gruber sat down with Adriana Bobinchock from the McLean Public Affairs Office for an interview to help clarify her work and talk about some of her comments that didn’t make the final cut on CNN.

AB: You’ve been conducting research on marijuana for the better part of two decades. How did you get into this field?
SG: Along with other McLean researchers, I was working on a series of projects designed to look at college students to assess the potential difference in cognitive function in those who smoked marijuana and those who did not. I found it absolutely fascinating. From there, my interest grew and I began to explore more specific questions about marijuana—for example, how it impacts brain function, structure and mood, and why some patients, for example those with bipolar disorder, seemed to use it more frequently than other substances.

Staci Gruber, PhD and Sanjay Gupta
Staci Gruber, PhD, sits down with CNN’s Sanjay Gupta, MD

AB: Although you’ve primarily been in the limelight recently regarding your research on medical marijuana, your work looking at recreational use of the drug has also been highly cited nationally. Can you tell us a bit more?
SG: Of course. One of my primary areas of interest is the impact of marijuana on brain and behavior in people who begin using regularly before the age of 16 as compared to those who don’t begin smoking until after 16. The results so far have been quite striking. Chronic marijuana smokers with earlier onset of use appear to have more difficulty with cognitive tasks, altered patterns of brain activation and less organized white matter compared to those who began smoking later or people who don’t smoke marijuana at all. Interestingly, later onset smokers don’t appear to have the same difficulty and appear more similar to those who have never smoked. We’re also looking at former marijuana smokers who have been abstinent for an extended period to figure out what happens when chronic smokers stop using marijuana.

AB: Does your work indicate that if recreational marijuana becomes legal in the United States that there should be age restrictions?
SG: We certainly need to be mindful about what we know with regard to the developing brain and how vulnerable it is to substances like drugs and alcohol. My work and that of my colleagues in this field is dedicated to answering a lot of complicated questions that are designed to help policymakers make sound, fact-based decisions.

AB: Medical marijuana is now legal in 23 states as well as in Washington, DC. With so much interest around this topic, how can people understand the difference between recreational and medical use of marijuana?
SG: Medical marijuana and recreational marijuana are not the same. For most people who use marijuana recreationally, they are interested in the experience. The idea is to get a psychoactive effect, which is why marijuana strains high in THC, the primary psychoactive component in marijuana, are so popular among recreational users. Whether they’re using a sativa strain, which is considered more ‘energizing’ and has been associated with more ‘heady’ effects or an indica strain, which most people say makes them feel ‘relaxed’ and ‘mellow’, they’re looking to change their current mental state. Generally, medical marijuana patients are seeking treatment for a range of physical or emotional issues. They just want to feel better and most often have no interest in experiencing a ‘high’. They often explore the use of strains high in cannabidiol, the major constituent in marijuana that is not psychoactive but which has shown tremendous promise for some conditions, or variable ratios of THC to CBD. There is a big difference between the two groups.

AB: Why do you think medical marijuana is being so rigorously contested by some groups?
SG: I think there are a number of issues that make the idea of medical marijuana difficult for some people to support. First of all, marijuana is still a Schedule I drug, which by definition indicates that there is no acceptable medical value, so that’s tough for people to reconcile at the same time states are passing legislation making the use of medical marijuana legal. For some, the notion that marijuana is ‘medicine’ is hard for some to support because the word medicine conveys a sense of consistency, regulation and oversight which simply isn’t in place at this point for marijuana. When you buy Advil in Tuscaloosa, Alabama, it’s the same Advil that you buy in Boston, Massachusetts. With medical marijuana, the strain that you buy in Massachusetts may be very different from what you would buy in New Mexico; variations in the composition (how much THC and CBD are contained, for example) and the potency are serious considerations.

AB: This past fall, you launched MIND (Marijuana Investigations for Neuroscientific Discovery)—what is it and why did you create it?
SG: Despite the fact that some states, like California, have had medical marijuana laws on the books since the 90s, I couldn’t find much in the scientific literature which focused on the impact of medical marijuana on cognitive function or other areas related to brain health. Policy appears to have outpaced science. At this point, we need scientific studies to begin to fill in the gaps. We need to understand if medical marijuana adequately addresses clinical symptoms and as a result may improve cognitive function, or if in fact there is a loss or impairment in cognitive function secondary to medical marijuana use. We also ultimately need to understand how specific cannabinoid-based products work—for example, how does strain A impact symptom X? MIND was conceptualized to begin to address some of these questions. Findings from the first phase of this study should ultimately foster a greater understanding of the impact of medical marijuana on cognitive function and overall brain health and may in turn facilitate the examination of the efficacy of medical marijuana for a range of conditions.

AB: You are currently in the initial phase of the first MIND study—tell us a bit more.
SG: In phase one, we aren’t offering anyone treatment—we are simply observing patients certified for medical marijuana use. We ask them to have a comprehensive evaluation with us before they begin their treatment with medical marijuana and then follow them over time. In addition to assessing cognitive function, brain structure, mood, sleep, and quality of life, we also get detailed information on the specific strains and types of marijuana products they use, how they use it, frequency and amount of use, etcetera. So far, the results are promising, as the majority of our research participants are reporting positive experiences with their treatment.

AB: In Weed 3, we met Amelia, one of the people enrolled in the MIND study. What have you observed to date regarding her experience in the study?
SG: Amelia’s story is really compelling. Compared to her baseline measures, Amelia’s self report scales after three months of treatment indicate a 60% reduction in symptoms of anxiety, and a 30% reduction in overall mood disturbance. She also reported a significant improvement in her quality of life and sleep, and noted that she has reduced the amount of alcohol she uses.

AB: Are you surprised by this preliminary data?
SG: To be honest, yes! This study is designed to assess a range of domains at baseline, and after three months, six months and one year of treatment. We thought we might see these kinds of results at later points in the study, but certainly not at three months.

AB: What is your view on medical marijuana?
SG: Medical marijuana in the US has been around for nearly two decades and is here to stay. We need to accept that concept and focus on conducting more clinical research projects. This may very well represent the next frontier of personalized medicine for those who derive a clinical benefit from medical marijuana. Every person is different and bound to have varied responses to the countless strains and types of cannabinoid-based products which will ultimately become available; this will require that patients are wholly invested in their own treatment and will need to ‘partner’ with their treaters. It’s also important to remember that as promising as cannabinoid therapies may be for many conditions or symptoms, it may not work for every illness or for every person and there is still far more that we don’t know than what we do know.

As a single case example, Amelia’s results give us a tremendous amount of hope that medical marijuana will be effective for many, but it is naive to assume that cannabinoid-based therapies will be a panacea for all that ails you.

AB: What are the next steps in terms of continued research into medical marijuana?
SG: There’s a lot to do! It is imperative to start with studies that are well designed and empirically sound that give us some idea what to expect for specific conditions and to facilitate educational opportunities for the community. As we better understand medical marijuana, we will also need to continue to look at the effects of recreational use. Our recreational studies remain critical given the increasing use of marijuana across the nation by youth at younger and younger ages.

Within the year, Dr. Gruber hopes to start phase two of her study where she will administer a cannabinoid-containing product to study participants and will monitor a range of domains including cognitive performance, mood, quality of life, sleep and brain structure and function.

Watch Dr. Gruber speak at the Aspen Brain Lab Conference or during an Institute of Politics John F. Kennedy Forum with Sanjay Gupta.