Study finds no long-term negative cognitive effects from marijuana

From Raw Story By Eric W. Dolan
Wednesday, July 11, 2012

While cognitive performance is negatively affected by cannabis use, the negative effects appear to completely wear off within a month, according to research published in the Experimental and Clinical Psychopharmacology in late June.

“With the number of cannabis users both illicitly and licitly increasing, the question of any potential lasting impact from cannabis use is increasingly important,” Amy M. Schreiner and Michael E. Dunn of the University of Central Florida wrote in their study.

Numerous studies have found that cannabis use affects memory, attention, perceptual-motor tasks, and other cognitive processes, but studies on how long these effects last has been inconsistent. The studies were complicated by the fact that psychoactive compounds in marijuana can linger in the body for days.

In hopes of better understanding the long-term, lasting effects of cannabis use, the researchers used a meta-analysis, a statistical procedure that allows researchers to mathematically summarize the results of a number of different studies.

Schreiner and Dunn’s study included two of these meta-analyses. The first was comprised of 33 studies that examined the cognitive effects of cannabis use after intoxication had worn off. The second was comprised of 13 studies that also examined the cognitive effects of cannabis use after intoxication had worn off, but this group of studies tested users after at least 25 days of abstinence.

The study found that cannabis use caused small impairments in attention, learning, and other cognitive processes that persisted after intoxication. However, the researchers said it was unclear if these minor impairments “translate[d] into practical impairments in functioning.” But the second meta-analysis suggested that these minor impairments don’t last longer than a month.

“While the first meta-analysis revealed a small significant negative effect for general performance and a number of cognitive domains, the clinical significance remains unclear,” Schreiner and Dunn explained. “A second meta-analysis focusing on studies with longer abstention periods was conducted and indicated no lasting residual effects on neurocognitive performance as a result of cannabis use… Whether differences seen in the initial days or weeks of abstinence are due to drug residue effects or withdrawal effects, after approximately 1 month these effects do not persist for the moderate to heavy user.”

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Researchers study neuroprotective properties in cannabis | Fox News

See our report on Melanie Dreher’s research here

With more states opting to legalize the sale of medical marijuana, researchers are taking a closer look at the use of cannabis to treat chronic illnesses

Watch video at Fox News

March 20, 2012

With more states opting to legalize the sale of medical marijuana, researchers are taking a closer look at the use of cannabis to treat chronic illnesses.

Dr. Manny Alvarez, senior managing health editor of FoxNews.com, recently sat down with the Medicine Hunter, Chris Kilham, to find out how it’s being studied. Continue reading

UC studies find promise in medical marijuana

As an $8.7-million state research effort comes to an end, investigators report that cannabis can significantly relieve neuropathic pain and reduce muscle spasms in MS patients.

More research is urged.

Read the Report Here

(Source Los Angeles Times 2.18.10)  With an innovative but little-known state program to study medical marijuana about to run out of money, researchers and political supporters said Wednesday the results show promise.

“It should take all the mystery out of whether it works. We’ve got the results,” said former state Sen. John Vasconcellos, who led the effort to create the 10-year-old Center for Medicinal Cannabis Research.

The center has nearly spent its $8.7-million allocation, sponsoring 14 studies at UC campuses, including the first clinical trials of smoked marijuana in the United States in more than two decades.

Much of the research is still underway or under review, but five studies have been published in scientific journals. Four showed that cannabis can significantly relieve neuropathic pain and one found that vaporizers are an effective way to use marijuana. Another study, submitted for publication, found that marijuana can reduce muscle spasms in multiple sclerosis patients.

Dr. Igor Grant, a neuropsychiatrist at UC San Diego who is the center’s director, called the pain studies “pretty convincing” and urged the federal government to pay for additional clinical studies.

With the state stuck in a daunting budget crisis, even the center’s advocates do not expect more support. “There is no state money at this time, unfortunately,” said state Sen. Mark Leno (D-San Francisco).

Since the center opened in 2000, medical marijuana use has spread rapidly in California, driven largely by doctors’ willingness to recommend it for a wide range of ailments. But little research has been done on its effectiveness, in part because researchers must win approval from federal agencies, including the Drug Enforcement Administration.

Grant said federal officials did not try to thwart the research, but noted that approval typically took 18 months. “We basically did a lot of the work for investigators in terms of jumping through the hoops,” he said.

The unusual scientific program, approved by the Legislature in 1999, was the result of negotiations between Vasconcellos and former Atty. Gen. Dan Lungren. The two were vigorous adversaries in the contentious debate over the 1996 initiative that approved the use of medical marijuana.

Lungren, now a Republican congressman from Gold River, argued that Californians were moving ahead without the research needed to show whether marijuana was useful as a medicine. “I said at that time, if we had scientific evidence, we ought to be guided by scientific evidence,” he said.

“I was shrewd enough to pick up on Lungren’s ‘Let’s do research,’ ” Vasconcellos said. Lungren said he was shrewd enough to accept.

Lungren said the results are helpful, but underscore that medical marijuana should be more tightly controlled and used only where it has been proven effective.

The center funded a range of research, including six studies of whether marijuana reduces neuropathic pain, which is caused by a damaged or abnormally functioning nervous system. A UC San Francisco study of patients with HIV-related pain found that 52% of those who smoked marijuana experienced significant relief.

“I think that clearly cannabis has benefits,” said Dr. Donald I. Abrams, a San Francisco oncologist who led that study. “This substance has been a medicine for 2,700 years; it only hasn’t been a medicine for 70.”

Abrams doubts that the research will alter the debate over marijuana. “Science has not been driving this train for a long time now. I think it’s all politics,” he said.

Grant was more optimistic: “We have a different administration, and they are looking at the science basis of many things.”

He said the research shows marijuana should no longer be classified as a Schedule I drug. “It is not a drug without value,” he said.

john.hoeffel@latimes.com

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New study: Marijuana is useful treatment for some pain related medical maladies

Research project is first of its kind in 20 years

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Read the full study

Scientific evidence exists that medical marijuana is a promising treatment for some specific pain related medical conditions, researchers from the University of California’s Center for Medicinal Cannabis Research said Wednesday.

State funded studies conducted over the past decade have found marijuana could be effective by itself or in combination with other drugs for conditions such as nerve pain associated with HIV and muscle spasms associated with multiple sclerosis.

“This study confirms all of the anecdotal evidence” of suffering eased by marijuana, said state Sen. Mark Leno, D-San Francisco.

Leno was accompanied at his state capital news conference by former state Sen. John Vasconcellos, D-Santa Clara, who authored the legislation commissioning this $8.7 million worth of research in the wake of the 1996 passage of Proposition 215 legalizing marijuana for medical purposes.

The study did not include many other medical conditions for which marijuana is currently prescribed because the researchers were restricted by funding and legal issues accessing patients.  (Source)


… another report on the study:
Marijuana’s benefits for treating pain subject of UCSD report
Researchers at the University of California’s San Diego-based Center for Medicinal Cannabis Research presented a report to the state Legislature Wednesday that concludes marijuana has a therapeutic value in treating pain.

Following five clinical trials, the researchers found there is “reasonable evidence that cannabis is a promising treatment” for some specific, pain-related medical conditions.

“We focused on illnesses where current medical treatment does not provide adequate relief or coverage of symptoms” said Dr. Igor Grant, the center’s director and executive vice chair of UCSD’s Department of Psychiatry.

“These findings provide a strong, science-based context in which policymakers and the public can begin discussing the place of cannabis in medical care,” Grant said.

The 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.

The center was established in 2000 to conduct clinical and pre-clinical trials of cannabinoids in an effort to answer the question “does marijuana have therapeutic value?”

With the passage of Proposition 215 in 1996, it became legal in California for seriously ill patients under the supervision of a physician to obtain and use marijuana for medical purposes.

This story was written and edited by City News Service staff.

See Also Science Daily: Studies Show Marijuana Has Therapeutic Value, Research Reported to Legislature

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Chronic High Doses of Cannabinoids Promote Hippocampal Neurogenesis

– By Bryan Perkins (Source AP)  “The recent discovery that the hippocampus is able to generate new neurons throughout a human’s lifespan has changed the way we think about the mechanisms of psychiatric disorders and drug addiction,” says Wen Jian and colleagues in a study published in the Journal of Clinical Investigation in 2005.

It appears that cannabinoids are able to modulate pain, nausea, vomiting, epilepsy, ischemic stroke, cerebral trauma, multiple sclerosis, tumors, and many other disorders.

Cannabinoids act on two types of receptors, the CB1 receptors (found mainly in the brain) and the CB2 receptors (found mainly in the immune system). The CB1 receptor is one of the most abundant G protein coupled receptors in the mammalian brain and it accounts for most, if not all, of the centrally mediated effects of cannabinoids. Cannabionoid receptors are evolutionarily conserved among various vertebrates and invertebrates which have been separate for 500 million years.

Hippocampal neurogenesis is suppressed following chronic administration of the major drugs of abuse (including opiates, alcohol, nicotine, and cocaine). However, CB1-knockout mice display significantly decreased hippocampal neurogenesis, suggesting that CB1 receptors activated by endogenous, plant-derived, or synthetic cannabinoids may promote hippocampal neurogenesis.

Wen Jiang and colleagues have given the first evidence suggesting that both embryonic and adult hippocampal neural stem/progenitor cells (NS/PCs) express CB1 receptors. Cannabinoids can regulate the proliferation of hippocampal NS/PCs by acting on CB1 receptors. They found that both the synthetic cannabinoid HU210 and the endocannabinoid anandamide profoundly promote embryonic hippocampal NS/PC proliferation.

Chronic, but not acute, HU210 significantly increases the number of newborn hippocampal neurons in adult rats by promoting NS/PC proliferation. These promoting effects are not the outcome of hippocampal neuronal death, as no neuronal loss or dying hippocampal neurons were detected following chronic HU210 injection. A significant increase was observed in the hipoppocampal newborn neurons of mice following twice-daily HU210 injection for 10 days.

It has been shown that acute, high doses of cannabinoids produce anxiety-like effects in rats and depression-like effects in mice. But chronic administration of high, but not low, doses of HU210 exerts anxiolytic- and antidepressant-like effects. This suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration. “This increase in hippocampal neurogenesis underlies the mechanism of anxiolytic- and andtidepressant-like effects produced by a high dose chronic HU210 treatment.”

Source: Jiang W, Zhang Y, Xiao L, Cleemput JV, Ji S-P, Bai G, & Zhang X (2005). Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects. Journal of Clinical Investigation, 115, 3104-3116

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Top Anti Drug Researcher Changes Mind, Says Legalize Marijuana

(Source)  For 30 years, Donald Tashkin has studied the effects of marijuana on lung function. His work has been funded by the vehemently anti-marijuana National Institute on Drug Abuse, which has long sought to demonstrate that marijuana causes lung cancer. After 3 decades of anti-drug research, here’s what Tashkin has to say about marijuana laws:

“Early on, when our research appeared as if there would be a negative impact on lung health, I was opposed to legalization because I thought it would lead to increased use and that would lead to increased health effects,” Tashkin says. “But at this point, I’d be in favor of legalization.
Tobacco smoking causes far more harm.   And in terms of an intoxicant, alcohol causes far more harm.

UCLA’s Tashkin studied heavy marijuana smokers to determine whether the use led to increased risk of lung cancer and chronic obstructive pulmonary disease, or COPD. He hypothesized that there would be a definitive link between cancer and marijuana smoking, but the results proved otherwise.

“What we found instead was no association and even a suggestion of some protective effect,” says Tashkin, whose research was the largest case-control study ever conducted.

Prejudice against marijuana and smoking in general runs so deep for many people that it just seems inconceivable that marijuana could actually reduce the risk of lung cancer.

But that’s what the data shows and it not only demolishes a major tenet of popular anti-pot propaganda, but also points towards a potentially groundbreaking opportunity to develop cancer cures through marijuana research.

Over and over again, all the bad things we’ve been told about marijuana are revealed to be not only false, but often the precise opposite of the truth.

~

Tashkin is discussing the results of his pulmonary research involving marijuana for the first time:

Even heavy, long-term marijuana smokers had no lung impairment after many years of smoking, and in fact tested slightly more healthy than those who didn’t smoke marijuana – “protective effect”.  He does mention, however, that the protective effect may only be present in heavy smokers, as they are getting a higher amount of the cannabinoids.

part 2:

See Also:

Marijuana / Cannabis Use In Pregnancy – Dr. Melanie Dreher

Update ~ Dreher’s research has hit mainstream media. See Fox news report. An excerpt 3.20.2012:

Melanie Dreher, who is the dean of nursing at Rush Medical Center in Chicago, did a study in Jamaica. It was actually published in the American Journal of Pediatricsin 1994, but now it’s re-circulating because of all the interest in the neuroprotective properties.

Basically, she studied women during their entire pregnancy, and then studied the babies about a year after birth. And what she studied was a group of women who did smoke cannabis during pregnancy and those who didn’t. She expected to see a difference in the babies as far as birth weight and neuro tests, but there was no difference whatsoever. The differences that the researchers did notice, that are unexplained and kind of curious are that the babies of the women who had smoked cannabis — and we’re talking about daily use during their pregnancy — socialized more quickly, made eye contact more quickly and were easier to engage.

We don’t know why this is so, but all the old saws of smoking during pregnancy will result in low birth weight did not show up — at least in the Jamaican study. In U.S. studies where we’ve seen a similar investigation, women have concurrently been abusing alcohol and other drugs as well.

See Also:

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The 30-day test showed that children of ganja-using mothers were superior to children of non-ganja mothers in two ways: the children had better organization and modulation of sleeping and waking, and they were less prone to stress-related anxiety.  (Melanie Dreher’s studies were funded by Patients Out of Time.)

The editors of Patients for Medical Cannabis were in attendance at the final hearing of the Iowa Pharmacy Board’s review of medical marijuana, where Dr. Melanie Dreher presented the results of her studies with “ganja babies” over the phone. (You can read her testimony on the second page here.) She has been studying the medical uses of ganja, as it’s called in Jamaica, for 30 years.

A quotation from Dreher’s testimony – “You know, people ask me all the time whether I think marijuana should be legalized, and I have been of the opinion for a long time that this is much ado about nothing. It is, compared to tobacco and alcohol, this is such a benign substance.

“It does not seem to make a difference in either the productivity of the people in Jamaica… it seems to make no difference in terms of exposure during pregnancy …We looked at these children again at age five, both groups of children, and could find absolutely nothing that linked their development with their exposure during pregnancy.

“I …would strongly support the decriminalization of cannabis, and now that we understand about the endocannabinoid system that this is documented, it’s researched… now that we have knowledge of why cannabis is good medicine, something that Jamaicans have known for years, I think it’s time to seriously revisit this product, to understand and be able to dispense it as medicine legally and to decriminalize the other uses of marijuana.”

No signs of birth defects

A landmark study conducted in the 1990s by medical anthropologist Dr. Dreher, (co-author of the book Women and Cannabis: Medicine, Science, and Sociology), gave the medical world a different insight into the use of marijuana by pregnant women in Jamaica. Dreher found that marijuana was being used in a cultural and medical context, as a way to relieve morning sickness or nausea, prevent depression and fatigue, and improve appetites. Her team observed both the mothers who used marijuana and their infants; they reported that there were no signs of birth defects or of behavioral problems in the marijuana-exposed children either during the month after birth or even several years after.

This is not to say that women should have no compunctions about using marijuana regularly and in large amounts during pregnancy. Rather, as scientists like Dreher argue, the medical community should improve its research methodologies, be more thorough, conduct more cross-cultural studies, and refrain from being so quick to conclude without solid evidence that any amount of marijuana use–no matter how slight–during pregnancy will do lasting harm to both mother and child. – Source

Melanie Dreher, RN, PhD, FAAN explains her cannabis and pregnancy research study in Jamaica. Pregnant women and their children were studied for over ten plus years, both marijuana smokers and non-smokers were included in the study – one of the first scientific studies of the effects that cannabis may have on pregnancy and the child’s development thereafter.

Prenatal Marijuana Exposure and Neonatal Outcomes in Jamaica:  An Ethnographic Study

“Although no positive or negative neurobehavioral effects of prenatal exposure were found at 3 days of life using the Brazelton examination, there were significant differences between the exposed and non-exposed neonates at the end of the first month.

Comparing the two groups, the neonates of mothers who used marijuana showed better physiological stability at 1 month and required less examiner facilitation to reach an organized state and become available for social stimulation.

The results of the comparison of neonates of the heavy-marijuana-using mothers and those of the non-using mothers were even more striking…

  • The heavily exposed neonates were more socially responsive and were more autonomically stable at 30 days than their matched counterparts.
  • quality of their alertness was higher;
  • their motor and autonomic systems were more robust;
  • they were less irritable;
  • they were less likely to demonstrate any imbalance of tone;
  • they needed less examiner facilitation to become organized;
  • they had better self-regulation;
  • judged to be more rewarding for caregivers than the neonates of non-using mothers at 1 month of age

Listen to Melanie Dreher in a 4 part radio interview:



The following comes from Dr. Melanie Dreher, reefer researcher

When Dreher released solidly researched reports showing that children of ganja-using mothers were better adjusted than children born to non-using mothers, she encountered political and professional turbulence.

Dr. Melanie Dreher is one of a handful of scientists who have researched marijuana objectively and intelligently in the last three decades.

Dr Dreher is Dean of the University of Iowa’s College of Nursing, and also holds the post of Associate Director for the University’s Department of Nursing and Patient Services. She’s a perpetual overachiever who earned honors degrees in nursing, anthropology and philosophy before being awarded a PhD in anthropology from prestigious Columbia University in 1977.

Although Dreher is a multi-faceted researcher and teacher whose expertise ranges from culture to child development to public health, she began early on to specialize in medical anthropology. After distinguishing herself as a field researcher in graduate school, Dreher was hand-picked by her professors to conduct a major study of marijuana use in Jamaica. Her doctoral dissertation was published as a book titled “Working Men and Ganja,” which stands as one of the premier cross-cultural studies of chronic marijuana use.

Along with being a widely-published researcher, writer, and college administrator, Dreher is a professor or lecturer at several institutions, including the University of the West Indies. She recently served as president of the 120,000 member Sigma Theta Tau International Nursing Honour Society, has been an expert witness in a religious freedom case involving ganja use by the Ethiopian Zion Coptic Church, and is one of the most well-respected academicians in the world.

This may explain why you hadn’t heard this news before:

from “Dreher’s Jamaican Pregnancy Study – More Suppression of Marijuana Research”

an excerpt:

Dreher decried “the politics of trying to get published.” She now sees it as “a miracle” that Pediatrics published her work on neonatal outcomes, however belatedly, in 1994. (Her paper on five-year outcomes came out in the West Indian Medical Journal before Pediatrics ran the neonatal outcomes.) She suspects that a review of “all the fugitive literature that’s out there that didn’t get published” would convey “a very different picture of prenatal cannabis exposure.”

Honest research is also impeded, Dreher said, by “the politics of building a research career. Most research is done by academics and academia is a very conservative environment where tenure often is more important than truth.” (Dreher is now Dean of the College of Nursing at the University of Iowa.)

The end result of biased science, Dreher observed, is a misinformed public. Recently, she “googled to see what was out there for the general public regarding pregnancy and marijuana.” Typical of the disinformation was an article entitled “Exposure to marijuana in womb may harm brain’ that began “Over the past decade several studies have linked behavior problems and lower IQ scores in children to prenatal use of marijuana…” A reference to Dreher said she had “written extensively on the benefits of smoking marijuana while smoking pregnant!”

See also:

Ganja mothers, ganja babies

Dreher Recounts Jamaican Study On Cannabis Use in Pregnancy

Editor’s note ~ If the public was given the truth regarding Cannabis, this recent suicide may have been prevented.

Reefer Madness is still ruining lives.