Published: Thursday 5 May 2016
According to new research at Western University, marijuana is the ultimate contradiction; at least when it comes to schizophrenia.
This first-of-its-kind study, published in the journal Neuroscience, demonstrates that a chemical found in marijuana called cannabidiol, or CBD, affects the brain in a way that makes it an ideal treatment option for schizophrenia. This research comes just months after the same lab found that adolescent exposure to THC, the other major compound found in marijuana, may lead to the onset of schizophrenia in adulthood.
"CBD is acting in a way that is the exact opposite to what THC is doing," said Steven Laviolette, PhD, associate professor at Western University's Schulich School of Medicine & Dentistry. "Within the same plant, you've got two different chemicals that are producing opposite effects in terms of psychiatric effects, molecular signaling and effects on the dopamine pathway."
Using pre-clinical models in rodents, Laviolette and his team, led by postdoctoral fellow Justine Renard, PhD, showed that CBD can normalize schizophrenia-like disturbances in the brain's dopamine system. By doing so, CBD alleviates schizophrenia-related symptoms linked to abnormal dopamine activity such as psychosis and cognitive problems. The researchers also demonstrated that the chemical is bypassing the molecular pathway in the brain that causes the negative side-effects typically seen in traditional antipsychotic medications.
"One of the biggest problems in treating schizophrenia is that there hasn't been an effective new treatment on the market in a very long time," said Laviolette. "The drugs on the market today have limited efficacy and horrible side effects; there is a desperate need for safer alternative medications."
While CBD has shown promise as a treatment for schizophrenia in previous studies, this research is the first to show exactly how it acts on the brain to have positive results in mitigating psychiatric symptoms without causing the fatigue, lack of motivation and other side-effects associated with traditional medications.
"When we measured the molecular changes that happened in the brain, we found that the effects of CBD were bypassing traditional molecular pathways that are activated by antipsychotic drugs. We think that's one of the reasons that it has better tolerability and fewer side-effects," he said.
By Bertha Madras April 29 2016
Each week, In Theory takes on a big idea in the news and explores it from a range of perspectives. This week, we’re talking about drug scheduling. Need a primer? Catch up here.
Bertha Madras is a professor of psychobiology at McLean Hospital and Harvard Medical School, with a research focus on how drugs affect the brain. She is former deputy director for demand reduction in the White House Office of National Drug Control Policy.
Data from 2015 indicate that 30 percent of current cannabis users harbor a use disorder — more Americans are dependent on cannabis than on any other illicit drug. Yet marijuana advocates have relentlessly pressured the federal government to shift marijuana from Schedule I — the most restrictive category of drug — to another schedule or to de-schedule it completely. Their rationale? “States have already approved medical marijuana”; “rescheduling will open the floodgates for research”; and “many people claim that marijuana alone alleviates their symptoms.”
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For those who are still concerned about ‘evidence based science’ and ‘best medical and pharmaceutical practice’…the following ‘open letter’ with attachments was sent to all Federal Senators, NSW and Victorian Premiers last week.
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Scott E. Hadland, MD, MPH,1,2 John R. Knight, MD,1,3 and Sion K. Harris, PhD1,2,3
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The publisher's final edited version of this article is available at J Dev Behav Pediatr
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Marijuana policy is rapidly evolving in the United States and elsewhere, with cannabis sales fully legalized and regulated in some jurisdictions and use of the drug for medicinal purposes permitted in many others. Amidst this political change, patients and families are increasingly asking whether cannabis and its derivatives may have therapeutic utility for a number of conditions, including developmental and behavioral disorders in children and adolescents. This review examines the epidemiology of cannabis use among children and adolescents, including those with developmental and behavioral diagnoses. It then outlines the increasingly well-recognized neurocognitive changes shown to occur in adolescents who use cannabis regularly, highlighting the unique susceptibility of the developing adolescent brain and describing the role of the endocannabinoid system in normal neurodevelopment. The review then discusses some of the proposed uses of cannabis in developmental and behavioral conditions, including attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Throughout, the review outlines gaps in current knowledge and highlights directions for future research, especially in light of a dearth of studies specifically examining neurocognitive and psychiatric outcomes among children and adolescents with developmental and behavioral concerns exposed to cannabis
Given the current scarcity of data, cannabis cannot be safely recommended for the treatment of developmental or behavioral disorders at this time. At best, some might consider its use as a last-line therapy when all other conventional therapies have failed.92,93 As marijuana policy evolves and as the drug becomes more readily available, it is important that practicing clinicians recognize the long-term health and neuropsychiatric consequences of regular use. Although a decades-long public health campaign has showcased the harms of cigarette smoking, similar movements to illustrate the hazards of cannabis use have not been as rigorous or successful. As a result, accurate information on regular cannabis use remains poorly disseminated to patients, families and physicians. Further, there are especially few studies examining neurocognitive and psychiatric outcomes among children and adolescents with developmental or behavioral concerns who are exposed to cannabis, and this remains a critical area for future study. In coming to the decision to use marijuana for medicinal purposes, all parties should be fully aware of the long-term hazards of regular cannabis use, recognize the lack of evidence on its efficacy in developmental and behavioral conditions, and incorporate this information into a careful risk-benefit analysis.
For complete paper (cited 5/4/16)
Wilkinson ST1, Stefanovics E, Rosenheck RA.
An increasing number of states have approved posttraumatic stress disorder (PTSD) as a qualifying condition for medical marijuana, although little evidence exists evaluating the effect of marijuana use in PTSD. We examined the association between marijuana use and PTSD symptom severity in a longitudinal, observational study.
From 1992 to 2011, veterans with DSM-III/-IV PTSD (N = 2,276) were admitted to specialized Veterans Affairs treatment programs, with assessments conducted at intake and 4 months after discharge. Subjects were classified into 4 groups according to marijuana use: those with no use at admission or after discharge ("never-users"), those who used at admission but not after discharge ("stoppers"), those who used at admission and after discharge ("continuing users"), and those using after discharge but not at admission ("starters"). Analyses of variance compared baseline characteristics and identified relevant covariates. Analyses of covariance then compared groups on follow-up measures of PTSD symptoms, drug and alcohol use, violent behavior, and employment.
After we adjusted for relevant baseline covariates, marijuana use was significantly associated with worse outcomes in PTSD symptom severity (P < .01), violent behavior (P < .01), and measures of alcohol and drug use (P < .01) when compared with stoppers and never-users. At follow-up, stoppers and never-users had the lowest levels of PTSD symptoms (P < .0001), and starters had the highest levels of violent behavior (P < .0001). After adjusting for covariates and using never-users as a reference, starting marijuana use had an effect size on PTSD symptoms of +0.34 (Cohen d = change/SD), and stopping marijuana use had an effect size of -0.18.
In this observational study, initiating marijuana use after treatment was associated with worse PTSD symptoms, more violent behavior, and alcohol use. Marijuana may actually worsen PTSD symptoms or nullify the benefits of specialized, intensive treatment. Cessation or prevention of use may be an important goal of treatment.
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