Category: Marijuana

Researchers from the University of California's Center for Medicinal Cannabis Research (CMCR) have found "reasonable evidence that cannabis is a promising treatment" for some specific, pain-related medical conditions. Their findings, presented February 17 to the California legislature and public, are included in a report available on the CMCR web site.

"We focused on illnesses where current medical treatment does not provide adequate relief or coverage of symptoms," explained CMCR director, Igor Grant, MD, Executive Vice-Chair of the Department of Psychiatry at the UCSD School of Medicine. "These findings provide a strong, science-based context in which policy makers and the public can begin discussing the place of cannabis in medical care."

Researchers have completed five scientific clinical trials, with more in progress. These studies showed that cannabis can be helpful in easing pain in selected syndromes caused by injury or diseases of the nervous system and possibly for painful muscle spasms due to multiple sclerosis.

"These scientists created an unparalleled program of systematic research, focused on science-based answers rather than political or social beliefs," said Senator John Vasconcellos, original author of The Medical Marijuana Research Act of 1999 (SB847) which led to the creation of the CMCR.

Study results have been published in high-impact medical journals, garnering national and international attention which prompted leading experts to come together and foster scientific dialog on the possible uses of cannabis as a therapeutic agent. More study will be necessary to figure out the mechanisms of action and the full therapeutic potential of cannabinoid compounds, according to the UC researchers.

 The benefits of marijuana in tempering or reversing the effects of Alzheimer's disease have been challenged in a new study by researchers at the University of British Columbia and Vancouver Coastal Health Research Institute.

The findings, published in the current issue of the journal Current Alzheimer Research, could lower expectations about the benefits of medical marijuana in combating various cognitive diseases and help redirect future research to more promising therapeutics.

Previous studies using animal models showed that HU210, a synthetic form of the compounds found in marijuana, reduced the toxicity of plaques and promoted the growth of new neurons. Those studies used rats carrying amyloid protein, the toxin that forms plaques in the brains of Alzheimer's victims.

The new study, led by Dr. Weihong Song, Canada Research Chair in Alzheimer's Disease and a professor of psychiatry in the UBC Faculty of Medicine, was the first to test those findings using mice carrying human genetic mutations that cause Alzheimer's disease — widely considered to be a more accurate model for the disease in humans.

"As scientists, we begin every study hoping to be able to confirm beneficial effects of potential therapies, and we hoped to confirm this for the use of medical marijuana in treating Alzheimer's disease," says Song, a member of the Brain Research Centre at UBC and VCH Research Institute and Director of Townsend Family Laboratories at UBC.

"But we didn't see any benefit at all. Instead, our study pointed to some detrimental effects."

Over a period of several weeks, some of the Alzheimer's-afflicted mice were given varying doses of HU210 — also known as cannabinoids — which is 100 to 800 times more potent than the marijuana compounds. Their memory was then tested.

The mice treated with HU210 did no better than untreated mice, with those given low doses of HU210 performing the worst. The researchers also found that HU210-treated mice had just as much plaque formation and the same density of neurons as the control group. The group given higher doses actually had fewer brain cells.

"Our study shows that HU210 has no biological or behavioural effect on the established Alzheimer's disease model," says Song, the Jack Brown and Family Professor and Chair in Alzheimer's Disease. "More studies should be done before we place much hope in marijuana's benefits for Alzheimer's patients."

Background

Alzheimer's disease is a neurodegenerative disorder characterized by progressive cognitive deterioration and is the most common form of dementia.

The Alzheimer Society of Canada estimates that the disease affects close to 300,000 Canadians and accounts for two-thirds of all cases of dementia. Approximately $5.5 billion per year is spent caring for persons with Alzheimer's and related dementias in Canada. By 2031, about 750,000 Canadians will suffer from Alzheimer's and related dementias.

The Alzheimer's Association in the U.S. estimates there are approximately 500,000 Americans younger than 65 with Alzheimer's or other dementia.

The research was supported by the Canadian Institutes of Health Research, the Jack Brown and Family Alzheimer's Research Foundation, the Michael Smith Foundation for Health Research and a donation from the David Townsend Family.

— Teens who frequently listen to music that contains references to marijuana are more likely to use the drug than their counterparts with less exposure to such lyrics, according to a University of Pittsburgh School of Medicine study online now in the journal Addiction.

"Based on an analysis of survey data from 959 ninth-graders, we found that students who listen to music with the most references to marijuana are almost twice as likely to have used the drug than their peers whose musical tastes favor songs less focused on substance use, even after controlling for confounding factors," said Brian Primack, M.D.,Ed.M., M.S., lead author of the study and assistant professor of medicine and pediatrics at Pitt's School of Medicine.

"Interestingly, we also found that exposure to marijuana in music was not associated with other high-risk behaviors, such as excessive alcohol consumption. This suggests that there is a real link between the marijuana lyrics and marijuana use," said Dr. Primack.

To accurately estimate marijuana exposure in music, researchers used an improved process to calculate the exposure, which incorporated student report of music exposure and favorite artists as well as intensive content analysis of the top 794 songs from 2005, 2006 and 2007 based on Billboard Magazine's year-end charts.

Researchers estimated that the average study participant listened to 21.8 hours of music per week and were exposed to an estimated 40 marijuana references in music per day. Twelve percent identified themselves as current marijuana users, with 32 percent identifying themselves as having previously tried the substance. Compared to those who cited a favorite artist with zero songs with cannabis references, students who identified a favorite artist with three or more songs with cannabis references had nearly double the odds of being current cannabis users.

Researchers controlled for such demographic variables as age, race, gender, parental education and school grades in analyzing the data.

"Although it may be that heavy exposure to music about marijuana causes marijuana smoking, it may also be that those who smoke marijuana seek out music with lyrics related to marijuana," noted

Dr. Primack. "In either case, these results may help us develop more effective programs on drug education. For example, media literacy programs may help young people more accurately analyze and evaluate the marijuana-related messages they are likely to hear in popular music."

Co-authors of the study are Erika L. Douglas and Kevin L. Kraemer, both of the University of Pittsburgh.

Dr. Primack is supported with funding from the National Institutes of Health, the Robert Wood Johnson Foundation and the Maurice Falk Foundation.

Journal Reference:

1. Brian A. Primack, Erika L. Douglas, & Kevin L. Kraemer. Exposure to cannabis in popular music and cannabis use among adolescents. Addiction, 2010; DOI: 10.1111/j.1360-0443.2009.02801.x

NewsPsychology (Dec. 21, 2009) — Progression to daily marijuana use in adolescence may hasten the onset of symptoms leading up to psychosis, an Emory University study finds. The study was published in the November issue of the American Journal of Psychiatry.

The researchers analyzed data from 109 hospitalized patients who were experiencing their first psychotic episode. The results showed that patients who had a history of using marijuana, or cannabis, and increased to daily pot smoking experienced both psychotic and pre-psychotic symptoms at earlier ages.

“We were surprised that it wasn’t just whether or not they used cannabis in adolescence that predicted the age of onset, rather it was how quickly they progressed to becoming a daily cannabis user that was the stronger predictor,” said Michael Compton, lead author and assistant professor of psychiatry in the Emory School of Medicine.

The study also found a gender difference: The female subjects who progressed to daily pot smoking had a greater increased risk for the onset of psychosis than the males.

Marijuana is the most abused illicit substance among people with schizophrenia, the most extreme form of psychosis, and previous research has shown that smoking pot is likely a risk factor for the disease.

The Emory study also focused on what is known as the prodromal period, when a person has symptoms such as unusual sensory experiences, which are often precursors to frank hallucinations and delusions. Prodromal symptoms can occur months, or years, before a diagnosis of psychosis. About 30 to 40 percent of prodomal teenagers will eventually develop schizophrenia or another psychotic disorder.

“The prodromal period is especially important because it’s considered to be a critical time for preventive intervention,” says Elaine Walker, a co-investigator of the study and professor of psychology and neuroscience at Emory.

The study also involved researchers from Emory’s Rollins School of Public Health and Georgia State University. It was funded by the National Institute of Mental Health.

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The above story is reprinted (with editorial adaptations by newsPsychology staff) from materials provided by Emory University.

Journal Reference:

1. Compton et al. Association of Pre-Onset Cannabis, Alcohol, and Tobacco Use With Age at Onset of Prodrome and Age at Onset of Psychosis in First-Episode Patients. American Journal of Psychiatry, 2009; 166 (11): 1251 DOI: 10.1176/appi.ajp.2009.09030311

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of NewsPsychology or its staff.

Marijuana is the most commonly used illicit drug in the United States. Roughly eight to 12 percent of marijuana users are considered "dependent" and, just like alcohol, the severity of symptoms increases with heavier use. A new study has found that use and misuse of alcohol and marijuana are influenced by a common set of genes.

Results will be published in the March 2010 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"Results from a large annual survey of high-school students show that in 2008, 41.8 percent of 12th graders reported having used marijuana," explained Carolyn E. Sartor, a research instructor at Washington University School of Medicine and corresponding author for the study. "Although many may have used the drug on only a few occasions, 5.4 percent of 12th graders reported using it daily within the preceding month."

"The active ingredient in marijuana is THC, which mimics natural cannabinoids that the brain produces," added Christian Hopfer, associate professor at the University of Colorado School of Medicine. "The cannabinoid system is critical for learning, memory, appetite, and pain perception. Most users of marijuana will not develop an 'addiction' to it, but perhaps one in 12 will. What is not commonly appreciated about marijuana use is that strong evidence has emerged that it increases the risk of developing mental illnesses and possibly exacerbates pre-existing mental illnesses."

"Like any drug, marijuana can be used in a way that negatively impacts quality of life, interfering with functioning at school or work or leading to problems with family and friends," said Sartor. "Although at least three of six symptoms listed in the Diagnostic and Statistical Manual of Mental Disorders — Fourth Edition (DSM-IV) are needed to meet full criteria for cannabis (marijuana) dependence … the presence of even one or two of these symptoms could create distress or interfere with day-to-day functioning. There is strong evidence for a genetic component to use and dependence on marijuana as well as alcohol, and the use (and misuse) of these substances frequently occur together."

Researchers examined 6,257 individuals (2,761 complete twin pairs and 735 singletons) listed in the Australian Twin Registry, 24 to 36 years of age. Alcohol and marijuana use histories were gathered in telephone diagnostic interviews and used to derive levels of alcohol consumption, frequency of marijuana use, and DSM-IV alcohol and cannabis dependence symptoms.

"Our findings indicate that … many of the same genetic factors that contribute to alcohol use also contribute to marijuana use," said Sartor. "Likewise, alcohol dependence symptoms and cannabis dependence symptoms can be traced to some of the same genetic influences. For both alcohol and marijuana, the majority of genetic factors that contribute to use also contribute to dependence symptoms."

"In other words," said Hopfer, "the genetic influences on drug use are not specific to individual drugs, but seem to influence a general tendency to engage in drug use. This is important to note because there is a tendency to study drugs in isolation — alcohol, tobacco, marijuana, cocaine, etc. These findings add support to the notion of common mechanisms underlying all addictions."

"The fact that very little of the environmental influences on alcohol and marijuana use, or on alcohol and cannabis dependence symptoms, could be traced to common sources indicates that there may be important distinctions between those environmental factors that influence alcohol-related outcomes and those that influence marijuana-related outcomes," said Sartor. "Identifying alcohol- and marijuana-specific risk factors is an important next step in this line of research."

"Marijuana research is relatively sparse compared to alcohol or nicotine research," added Hopfer. "However, if you look at reports of at least adolescents and young people using, it becomes clear that marijuana use, including daily marijuana use, is quite common and the effects of this are not well understood. The mental illness/marijuana connection has not received much press, although I think the evidence has grown substantially that marijuana is a causal risk factor for the development of mental illness."

Canadian teenagers are among the largest consumers of cannabis worldwide. The damaging effects of this illicit drug on young brains are worse than originally thought, according to new research by Dr. Gabriella Gobbi, a psychiatric researcher from the Research Institute of the McGill University Health Centre. The new study, published in Neurobiology of Disease, suggests that daily consumption of cannabis in teens can cause depression and anxiety, and have an irreversible long-term effect on the brain.

"We wanted to know what happens in the brains of teenagers when they use cannabis and whether they are more susceptible to its neurological effects than adults," explained Dr. Gobbi, who is also a professor at McGill University. Her study points to an apparent action of cannabis on two important compounds in the brain — serotonin and norepinephrine — which are involved in the regulation of neurological functions such as mood control and anxiety.

"Teenagers who are exposed to cannabis have decreased serotonin transmission, which leads to mood disorders, as well as increased norepinephrine transmission, which leads to greater long-term susceptibility to stress," Dr. Gobbi stated.

Previous epidemiological studies have shown how cannabis consumption can affect behaviour in some teenagers. "Our study is one of the first to focus on the neurobiological mechanisms at the root of this influence of cannabis on depression and anxiety in adolescents," confirmed Dr. Gobbi. It is also the first study to demonstrate that cannabis consumption causes more serious damage during adolescence than adulthood.

Dr. Gabriella Gobbi is a researcher at the neuroscience axis of the Research Institute of the McGill University Health Centre and also a psychiatrist and associate professor at the Department of Psychiatry, McGill University.

This study was funded by a grant from The Canadian Psychiatric Research Foundation (CPRF)

This article was co-authored by Dr. Francis Rodriguez Bambico; Ms. Nhu-Tram Nguyen, and Mr. Noam Katz from from IR-MUHC and the Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University.

Cannabis can reduce spasticity in multiple sclerosis (MS) patients. A systematic review, published in the open access journal BMC Neurology, found that five out six randomized controlled trials reported a reduction in spasticity and an improvement in mobility.

Shaheen Lakhan and Marie Rowland from the Global Neuroscience Initiative Foundation, Los Angeles, USA, searched for trials evaluating the cannabis extracts delta9-tetrahydrocannabinol (THC) and cannabidiol (CBD). According to Lakhan, "We found evidence that combined THC and CBD extracts may provide therapeutic benefit for MS spasticity symptoms."

Spasticity, involuntary muscle tension or contraction, is a common symptom of MS. Many existing therapies for this symptom are ineffective, difficult to obtain, or associated with intolerable side effects. In this study, reported incidence of side effects from cannabis, such as intoxication, varied greatly depending on the amount of cannabis needed to effectively limit spasticity, but the researchers note that side effects were also seen in the placebo groups. They add, "Considering the distress and limitations spasticity brings to individuals with MS, it is important to carefully weigh the potential for side effects with the potential for symptom relief ."

Lakhan concludes, "The therapeutic potential of cannabinoids in MS is comprehensive and should be given considerable attention."

Journal Reference:

1. Shaheen E Lakhan and Marie Rowland. Whole plant cannabis extracts in the treatment of spasticity in multiple sclerosis: a systematic review. BMC Neurology,

Substituting cannabis in place of more harmful drugs may be a winning strategy in the fight against substance misuse. Research published in BioMed Central' open access Harm Reduction Journal features a poll of 350 cannabis users, finding that 40% used cannabis to control their alcohol cravings, 66% as a replacement for prescription drugs and 26% for other, more potent, illegal drugs.

Amanda Reiman, from the University of California, Berkeley, USA, carried out the study at Berkeley Patient's Group, a medical cannabis dispensary. She said, "Substituting cannabis for alcohol has been described as a radical alcohol treatment protocol. This approach could be used to address heavy alcohol use in the British Isles — people might substitute cannabis, a potentially safer drug than alcohol with less negative side-effects, if it were socially acceptable and available."

Reiman found that 65% of people reported using cannabis as a substitute because it has less adverse side effects than alcohol, illicit or prescription drugs, 34% because it has less withdrawal potential and 57.4% because cannabis provides better symptom management. She said, "This brings up two important points. First, self-determination, the right of an individual to decide which treatment or substance is most effective and least harmful for them. Secondly, the recognition that substitution might be a viable alternative to abstinence for those who can't or won't completely stop using psychoactive substances."

Speaking about legalization of cannabis, Reiman added, "The economic hardship of The Great Depression helped bring about the end of alcohol prohibition. Now, as we are again faced with economic struggles, the US is looking to marijuana as a potential revenue generator. Public support is rising for the legalization of recreational use and remains high for the use of marijuana as a medicine. The hope is that this interest will translate into increased research support and the removal of current barriers to conducting such research, such as the Schedule I/Class B status of marijuana."

Journal Reference:

1. Amanda Reiman. Cannabis as a Substitute for Alcohol and Other Drugs. Harm Reduction Journal, 2009; 

 Marijuana is the most widely used illicit drug by adolescents, with almost 42% of high school seniors admitting to having experimented with it. Continued marijuana use may result in a number of serious consequences including depression, cognitive impairment, cardiovascular disease, and certain forms of cancer. As such, it is critical to prevent marijuana use by adolescents and numerous behavioral and medical scientists have been trying to establish the best means of prevention.

Many studies have focused on parents as being the best avenue for preventing adolescent marijuana use. Specifically, parental monitoring (when the parents know where their children are, who they are with, and what they are doing) has been seen as attenuating a number of negative adolescent behaviors, including gambling, sexual activity, and drug use. However, the strength of the relationship between monitoring and marijuana usage has been unclear; for example, if adolescents use marijuana, they may be more likely to hide that from their parents, compared to other behaviors. Despite this uncertainty, millions of dollars are spent annually on programs and media campaigns that urge parents to monitor their children’s behavior.

Psychologists Andrew Lac and William Crano from Claremont Graduate University reviewed numerous studies to examine the connection between parental monitoring and adolescent marijuana use. For this review, Lac and Crano selected 17 studies from the literature, which contained data on over 35,000 participants. Criteria the researchers used for selecting studies included adolescent participants, that the research focused exclusively on marijuana, and that parental monitoring was evaluated by adolescent self-reports, not parents’ reports of their own monitoring behavior.

Results of this comprehensive analysis, reported in the current issue of Perspectives on Psychological Science, a journal of the Association for Psychological Science, reveal that there is in a fact a strong, reliable link between parental monitoring and decreased marijuana usage in adolescents. In addition, the strongest effects were seen in the female-only studies.

The authors note, “Our review suggests that parents are far from irrelevant, even when it comes to an illegal and often secretive behavior on the part of their children.” They conclude that the information gleaned from this analysis may be useful for marijuana-based prevention programs that target parents and might provide some insight into alleviating risky adolescent behavior.

Journal Reference:

1. Lac et al. Monitoring Matters: Meta-Analytic Review Reveals the Reliable Linkage of Parental Monitoring With Adolescent Marijuana Use. Perspectives on Psychological Science, 2009; 4 (6): 578 DOI: 10.1111/j.1745-6924.2009.01166.x

Use of cannabinoids (marijuana) could assist in the treatment of post-traumatic stress disorder patients. This is exposed in a new study carried out at the Learning and Memory Lab in the University of Haifa's Department of Psychology.

The study, carried out by research student Eti Ganon-Elazar under the supervision of Dr. Irit Akirav, was published in the Journal of Neuroscience.

In most cases, the result of experiencing a traumatic event — a car accident or terror attack — is the appearance of medical and psychological symptoms that affect various functions, but which pass. However, some 10%-30% of people who experience a traumatic event develop post-traumatic stress disorder, a condition in which the patient continues to suffer stress symptoms for months and even years after the traumatic event. Symptoms include reawakened trauma, avoidance of anything that could recall the trauma, and psychological and physiological disturbances. One of the problems in the course of treating trauma patients is that a person is frequently exposed to additional stress, which hinders the patient's overcoming the trauma.

The present study, carried out by Dr. Akirav and research student Eti Ganon-Elazar, aimed to examine the efficiency of cannabinoids as a medical treatment for coping with post-traumatic stress. The researchers used a synthetic form of marijuana, which has similar properties to the natural plant, and they chose to use a rat model, which presents similar physiological responses to stress to that of humans.

The first stage of the research examined how long it took for the rats to overcome a traumatic experience, without any intervention. A cell colored white on one side and black on the other was prepared. The rats were placed in the white area, and as soon as they moved over to the black area, which they prefer, they received a light electric shock. Each day they were brought to the cell and placed back in the white area. Immediately following exposure to the traumatic experience, the rats would not move to the black area voluntarily, but a few days later after not receiving further electric shocks in the black area, they learned that it is safe again and moved there without hesitation.

Next, the researchers introduced an element of stress. A second group of rats were placed on a small, elevated platform after receiving the electric shock, which added stress to the traumatic experience. These rats abstained from returning to the black area in the cell for much longer, which shows that the exposure to additional stress does indeed hinder the process of overcoming trauma.

The third stage of the research examined yet another group of rats. These were exposed to the traumatic and additional stress events, but just before being elevated on the platform received an injection of synthetic marijuana in the amygdala area of the brain — a specific area known to be connected to emotive memory. These rats agreed to enter the black area after the same amount of time as the first group — showing that the synthetic marijuana cancelled out the symptoms of stress. Refining the results of this study, the researchers then administered marijuana injections at different points in time on additional groups of rats, and found that regardless of when exactly the injection was administered, it prevented the surfacing of stress symptoms.

Dr. Akirav and Ganon-Elazar also examined hormonal changes in the course of the experiment and found that synthetic marijuana prevents increased release of the stress hormone that the body produces in response to stress.

According to Dr. Akirav, the results of this study show that cannabinoids can play an important role in stress-related disorders. "The results of our research should encourage psychiatric investigation into the use of cannabinoids in post-traumatic stress patients," she concludes.