Cannabis: A new frontier in therapeutics

Wile debate about recreational marijuana use continues, researchers are investigating the effectiveness of cannabis for treating pain, spasticity, and a host of other medical problems. In a symposium organized by the McGill University Health Centre (MUHC) as part of the 2015 American Association for the Advancement of Science Annual Meeting held this week in San Jose, California,  experts from North America and the U.K. share their perspectives on the therapeutic potential of medical cannabis and explore the emerging science behind it.

"We need to advance our understanding of the role of cannabinoids in health and disease through research and education for patients, physicians and policy-makers," says Dr. Mark Ware, director of clinical research at the Alan Edwards Pain Management Unit at the MUHC, in Canada.

As a pain specialist Dr. Ware regularly sees patients with severe chronic pain at his clinic in Montreal, and for some of them, marijuana appears to be a credible option. "I don't think that every physician should prescribe medical cannabis, or that every patient can benefit but it's time to enhance our scientific knowledge base and have informed discussions with patients."

Increasing numbers of jurisdictions worldwide are allowing access to herbal cannabis, and a range of policy initiatives are emerging to regulate its production, distribution, and authorization. It is widely believed that there is little evidence to support the consideration of cannabis as a therapeutic agent. However, several medicines based on tetrahydrocannabinol (THC), the psychoactive ingredient of cannabis, have been approved as pharmaceutical drugs.

Leading British cannabis researcher Professor Roger Pertwee, who co-discovered the presence of tetrahydrocannabivarin (THCV) in cannabis in the 70's, recently published with collaborators some findings of potential therapeutic relevance in the British Journal of Pharmacology. "We observed that THCV, the non-psychoactive component of cannabis, produces anti-schizophrenic effects in a preclinical model of schizophrenia," says Pertwee, professor of Neuropharmacology at Aberdeen University. "This finding has revealed a new potential therapeutic use for this compound."

Neuropsychiatrist and Director of the Center for Medicinal Cannabis Research (CMCR) at the University of California, San Diego Dr. Igor Grant is interested in the short and long-term neuropsychiatric effects of marijuana use. The CMCR has overseen some of the most extensive research on the therapeutic effects of medical marijuana in the U.S. "Despite a commonly held view that cannabis use results in brain damage, meta analyses of extensive neurocognitive studies fail to demonstrate meaningful cognitive declines among recreational users," says Dr. Grant. "Bain imaging has produced variable results, with the best designed studies showing null findings."

Dr. Grant adds that while it is plausible to hypothesize that cannabis exposure in children and adolescents could impair brain development or predispose to mental illness, data from properly designed prospective studies is lacking.

Tomado de sciencedaily.com

FUente: McGill University Health Centre. (2015, February 15). Cannabis: A new frontier in therapeutics. ScienceDaily. Retrieved February 16, 2015 from www.sciencedaily.com/releases/2015/02/150215070209.htm

Cannabis use in adolescence has negative impact on education

A study looks to add more fuel to the heated debate around the use of marijuana, as researchers have linked the frequent use of cannabis among adolescents with reduced educational attainment. The study also links frequent use of the drug with other negative health outcomes, such as suicide attempts.


The study's lead author, Dr. Edmund Silins, says that the results "provide strong evidence that the prevention or delay of cannabis use is likely to have broad health and social benefits."

The team, comprised of researchers from Australia and New Zealand, received funding from the Australian Government National Health and Medical Research Council, and the study has been published in The Lancet Psychiatry.


Many researchers are pushing for cannabis to be used in a therapeutic capacity, as a form of pain relief or to alleviate symptoms of conditions such as multiple sclerosis (MS) and post-traumatic stress disorder(PTSD).

However, study author Richard Mattick believes that moves toward the decriminalization and legalization of cannabis also contribute toward "raising the possibility that the drug might become more accessible to young people."

Outside of legal avenues, cannabis is the most widely used illicit drug worldwide. The National Institute on Drug Abuse (NIDA) report that around 7% of US high-school seniors are daily or near-daily cannabis users, with around 46% having tried the drug at some point during their lifetime.

Although the study uses data from adolescents in Australia and New Zealand, the authors state that the rates of cannabis use are similar across high-income countries. For example, they cite that the rates of cannabis use among adults in Australia and New Zealand are 10% and 15% respectively, compared with a rate of 15% in the US.

Does early cannabis use compromise education?

For the study, the researchers utilized the data of 3,765 participants from three large, long-term longitudinal studies, tracking cannabis use alongside several developmental outcomes from before the age of 17 up to the age of 30.

They recorded the frequency of cannabis use as never, less than monthly, monthly or more, weekly or more, or daily. The researchers chose to record the following developmental outcomes:

• Cannabis dependence
• Completing high school
• Depression
• Obtaining a university degree
• Suicide attempts
• Use of other illicit drugs
• Welfare dependence.

The researchers found significant associations between the frequency of adolescent cannabis use and all of the designated developmental outcomes. After adjusting for potential confounding factors such as socioeconomic status and mental illness, they found that five of the associations remained significant.

Individuals who had used cannabis daily before the age of 17 were 60% less likely to complete high school or obtain a degree than those who had never used cannabis. They were also 18 times more likely to become dependent on cannabis, eight times more likely to use other illicit drugs and seven times more likely to attempt suicide by the age of 25.

Most significantly, the researchers found that the risk of negative developmental outcomes increased relative to the frequency of the cannabis dose. Daily cannabis users experienced the strongest effects of the association.

Impact on reforming legislation


In a linked commentary, Prof. Merete Nordentoft, of the University of Copenhagen, Denmark, explains why these results may have occurred:

"Persistent cannabis use has adverse effects, such as low energy and initiative, and impairment of cognitive functions, and these factors are likely to mediate the harmful effect of cannabis on educational attainment."

The authors say that these findings are consistent with the results of previous studies investigating early cannabis use alongside these developmental outcomes. They suggest that preventing or delaying cannabis use in adolescents could have far-reaching benefits, both socially and with regard to health.

One measure that the authors suggest could be implemented is screening for cannabis use in adolescents as standard practice during visits to doctors, child psychiatrists, school nurses and other health care practitioners. This is due to an estimated lack of self-reporting among adolescent cannabis users.

"Efforts to reform cannabis legislation should be carefully assessed to ensure they reduce adolescent cannabis use and prevent potentially adverse effects on adolescent development," says Dr. Silins.

In spite of this, the authors also acknowledge that within US states where cannabis has been made increasingly available for medical use, there has been no reported increase in use among young people.

The study still urges caution. The landscape is undeniably changing with regard to how cannabis is perceived and utilized, and the authors believe that as this framework changes, the needs of the youth must always be considered in order to prevent adverse developmental outcomes.

Tomado de: Medical News Today. Written by James McIntosh

APA: Regular marijuana use bad for teens' brains

As presented at the Annual Convention of the American Psychological Association

Frequent marijuana use can have a significant negative effect on the brains of teenagers and young adults, including cognitive decline, poor attention and memory, and decreased IQ, according to psychologists discussing public health implications of marijuana legalization at at APA, held in Washington, D.C., in August. 
     “It needs to be emphasized that regular cannabis use, which we consider once a week, is not safe and may result in addiction and neurocognitive damage, especially in youth,” said Krista Lisdahl, PhD, director of the brain imaging and neuropsychology lab at University of Wisconsin-Milwaukee. 
Brain imaging studies of regular marijuana users have shown significant changes in their brain structure, particularly among adolescents, Dr. Lisdahl said. Abnormalities in the brain’s gray matter, which is associated with intelligence, have been found in 16- to 19-year-olds who increased their marijuana use in the past year, she said. These findings remained even after researchers controlled for major medical conditions, prenatal drug exposure, developmental delays, and learning disabilities, she added. 
     “When considering legalization, policymakers need to address ways to prevent easy access to marijuana and provide additional treatment funding for adolescent and young adult users,” she said. She also recommended that legislators consider regulating levels of tetrahydrocannabinol, or THC, the major psychoactive chemical in marijuana, in order to reduce potential neurocognitive effects. 

Tomado de: Reportes de Congresos.  Univadis.com