Presently, 31 states have legalized marijuana for medicinal use, while 9 have done so for recreational use. Marijuana Policy Project reports that over 2.8 million Americans have used cannabis for medical purposes. More than 22.2 million people used it for recreation in 2015, according to a nationwide poll.

Associate professor of psychiatry at Harvard Medical School and neuroscientist Staci Gruber, PhD, says of marijuana, "Marijuana is like rock 'n' roll; it's here to stay." To get a medical marijuana card go to https://happymd.org/.

 

While there has been a meteoric rise in the acceptance of marijuana's recreational use, there has been a correspondingly slow development of knowledge about the drug's therapeutic potential, particularly in regard to the impact of marijuana on mental health and other domains. The gap in knowledge has motivated scientists like Gruber to continue studying cannabis despite the many challenges presented by its uncertain legal status.

 

Given the prevalence of marijuana usage, "it is my responsibility to assist patients and customers find out the absolute best methods in which they may be able to utilize these products safely and successfully," says Gruber.

 

Health consequences of cannabis and its 113 chemical compounds, termed cannabinoids, were the subject of a 2017 assessment by the National Academies of Sciences, Engineering, and Medicine. The review looked at numerous studies published since 1999 and concluded that only three therapeutic uses were supported by substantial or conclusive evidence: the treatment of chronic pain, the reduction of nausea caused by chemotherapy treatment, and the reduction of spasticity associated with multiple sclerosis.

 

"Despite what we hear in the media and contrary to popular assumption, there truly is very little known about the therapeutic effects in the human population," says Ziva Cooper, PhD, associate professor of clinical neurobiology at Columbia University Medical Center and one of the review's authors.

 

According to the study, 94% of Coloradans with medical marijuana ID cards reported suffering from "serious pain" as their primary motivation for doing so. The research also found that cannabis and cannabinoids significantly reduced pain compared to a placebo in 27 randomized studies including over 2,500 people with chronic pain, most of whom suffered from neuropathy.

 

In light of these findings, Cooper investigated further into the possibility that cannabis might assist lessen or even eliminate the need for opioids in pain management. She said that cannabis have been shown in animal experiments to minimize the amount of opioids required to achieve the desired effect of reducing pain. Studies published in JAMA Internal Medicine show that in jurisdictions where medicinal marijuana is permitted, both prescription opioid usage and opioid-related mortality rates are down (Vol. 174, No. 10, 2014, and Vol. 178, No. 5, 2018).

 

Cooper and coworkers performed a double-blind, placebo-controlled research of cannabis and opioids to determine the effectiveness of cannabis for pain management (Neuropsychopharmacology, Vol. 43, 2018). By submerging their hands in ice water, researchers were able to assess the pain thresholds and tolerance levels of otherwise healthy people. Strong pain alleviation was seen when researchers gave patients a combination of cannabis and a very low dosage of an opioid that was not effective on its own.

 

Cooper says, "It was really promising." Evidence suggests cannabinoids may be a useful complement to opioids for pain management, and may even mitigate some of the negative side effects of those drugs.

 

She plans to use a similar method in her next research that investigates the effects of combining cannabis with varying doses of cannabinoids and opioids. Cooper wants to discover whether the main psychoactive component of cannabis, tetrahydrocannabinol (THC), is essential for pain alleviation. She wants to see whether cannabidiol (CBD), another non­psychoactive cannabinoid, has the same effect.

 

Not enough research has been done

The effects of these two cannabinoids are being studied by Marcel Bonn-Miller, PhD, an adjunct assistant professor of psychology in psychiatry at the University of Pennsylvania. His focus is on the psychological discomfort associated with post-traumatic stress disorder (PTSD).

 

Bonn-Miller heard numerous patients mention using marijuana to improve symptoms when he initially began researching the condition 15 years ago at the University of Vermont, but he could only locate two published studies on cannabis and PTSD. "There was just this tremendous chasm that needed to be filled," he adds.

 

Behavioral treatments, such as extended exposure and cognitive processing therapy, are often used to treat PTSD in patients today. Some patients benefit greatly from these therapies, while others may not. "Many individuals are trying to find treatment," Bonn-Miller adds. "And there aren't any good drugs," she said.

 

Bonn-Miller is in charge of two massive, long-term research on the effects of cannabis on PTSD. The first is a randomized, controlled experiment that looks at several cannabinoids side by side. About 76 people, largely military veterans with post-traumatic stress disorder, are taking part in the study and are being randomly assigned to one of four groups to receive either a high THC strain of cannabis, a high CBD strain of cannabis, an equal THC/CBD strain of cannabis, or a placebo.

 

All of the cannabis utilized in this study comes from the University of Mississippi, the only legal source for cannabis used in scientific settings. (It's important to note, though, that street-level cannabis is often far more potent and comes in a wider variety of strains than what's cultivated on campus.)

 

The second project that Bonn-Miller is working on is an effort to solve this issue. Half of the 150 people participating in the observational research have reported using cannabis acquired from dispensaries in Denver. Half of the population does not participate in this practice. Researchers led by Bonn-Miller will monitor PTSD symptoms and cannabis use patterns quarterly for a full year.

 

To this end, Mallory Loflin, PhD, a research scientist at the VA San Diego Healthcare System's Center of Excellence for Stress and Mental Health, is conducting a double-blind placebo-controlled trial to investigate the potential benefits of CBD in tandem with extended exposure treatment. Prolonged exposure therapy is one of the most successful treatments for post-traumatic stress disorder (PTSD), but it's not a panacea and may be emotionally taxing for some patients. Loflin will investigate whether or if the use of CBD improves the tolerance and effectiveness of extended exposure treatment for people with post-traumatic stress disorder.

 

This is the first study of its kind to examine the effects of cannabis, and it will enroll 136 veterans with post-traumatic stress disorder (PTSD).

 

When the high is over

Marijuana Investigations for Neuroscientific Discovery, which Gruber directs, is privately supported as well (MIND). Initiated in 2014, MIND's goal is to investigate how cannabis and cannabinoids influence patients' cognitive abilities, reliance on conventional medications, quality of sleep, general well-being, measurements of brain structure and function, and mental health.

 

Although Gruber has spent over 20 years working with recreational pot smokers in his role as head of the Cognitive and Clinical Neuroimaging Core at McLean Hospital's Brain Imaging Center, the MIND initiative is dedicated to the study of medicinal marijuana users, who present unique challenges.

 

Many of Gruber's medical marijuana patients tell her they don't want to get high; they simply want to feel better, in contrast to the common belief among recreational users that they do it in order to alter their mental states.

 

Multiple studies have been undertaken by MIND on medicinal marijuana users to assess the effects of the drug on their brain function over the course of a year or more.

 

Patients who used cannabis for a variety of medical conditions, including anxiety, showed significant improvements in several areas, including cognitive function, symptom reduction (both general and specific), and reduced reliance on conventional medications (such as opioids, benzodiazepines, and other mood stabilizers and antidepressants).

 

These findings prompted and influenced Gruber's randomized, double-blind, placebo-controlled clinical study of a whole-plant, high-CBD tincture for the treatment of anxiety in patients. While some studies have found a negative connection between smoked whole-plant marijuana and social anxiety specifically, there has yet to be a double- blind placebo-controlled trial looking at CBD and anxiety. Gruber believes that the results of this first-ever clinical research on CBD will be able to fill in many gaps in our knowledge. Signing up test subjects is the first step in starting the experiment.

 

Even though studying medicinal marijuana is difficult, Gruber shares the optimism of many other experts in the area.