Why teenagers should steer clear of cannabis

[Micklemouse]

More grist to the gateway theory mill? From New Scientist
http://www.newscientist.com/article/...r&nsref=dn9488

Why teenagers should steer clear of cannabis

• 16:21 05 July 2006
• NewScientist.com news service
• Gaia Vince

Adolescents' use of marijuana may increase the risk of heroin addiction later in life, a new study suggests. Researchers say the work adds to "overwhelming" evidence that people under 21 should not use marijuana because of the risk of damaging the developing brain.
The idea that smoking cannabis increases the user's chance of going on to take harder drugs such as heroin is highly contentious. Some dub cannabis a “gateway” drug, arguing that peer pressure and exposure to drug dealers will tempt users to escalate their drug use. Others insist that smoking cannabis is unrelated to further drug use.
Now research in rats suggests that using marijuana reduces future sensitivity to opioids, which makes people more vulnerable to heroin addiction later in life. It does so by altering the brain chemistry of marijuana users, say the researchers.
“Adolescents in particular should never take cannabis – it’s far too risky because the brain areas essential for behaviour and cognitive functioning are still developing and are very sensitive to drug exposure,” says Jasmin Hurd, who led the study at the Karolinska Institute in Sweden.
But Hurd acknowledges that most people who use cannabis begin in their teens. A recent survey reported that as many as 20% of 16-year-olds in the US and Europe had illegally used cannabis in the previous month.
"Teenage" rats

In order to explore how the adolescent use of cannabis affects later drug use, Hurd and colleagues set up an experiment in rats aimed to mirror human use as closely as possible.
In the first part of the trial, six “teenage” rats were given a small dose of THC – the active chemical in cannabis – every three days between the ages of 28 and 49 days, which is the equivalent of human ages 12 to 18. The amount of THC given was roughly equivalent to a human smoking one joint every three days, Hurd explains. A control group of six rats did not receive THC.
One week after the first part was completed, catheters were inserted in all 12 of the adult rats and they were able to self-administer heroin by pushing a lever.
“At first, all the rats behaved the same and began to self-administer heroin frequently,” says Hurd. “But after a while, they stabilised their daily intake at a certain level. We saw that the ones that had been on THC as teenagers stabilised their intake at a much higher level than the others – they appeared to be less sensitive to the effects of heroin. And this continued throughout their lives.”
Hurd says reduced sensitivity to the heroin means the rats take larger doses, which has been shown to increase the risk of addiction.
Drug memory

The researchers then examined specific brain cells in the rats, including the opioid and cannabinoid receptors. They found that the rats that had been given THC during adolescence had a significantly altered opioid system in the area associated with reward and positive emotions. This is also the area linked to addiction.
“These are very specific changes and they are long-lasting, so the brain may ‘remember’ past cannabis experimentation and be vulnerable to harder drugs later in life,” Hurd says.
Neurologist Jim van Os, a cannabis expert at the University of Maastricht in the Netherlands told New Scientist the research was a welcome addition to our understanding of how cannabis affects the adolescent brain.
“The issue of cross-sensitisation of cannabis/opioid receptors has been a controversial one, but these findings show the drug’s damaging effects on the reward structures of the brain,” van Oshe says. “There is now overwhelming evidence that nobody in the brain’s developmental stage – under the age of 21 – should use cannabis.”
The research appears in the online edition of Neuropsychopharmacology

Remember kittlings, people, on the whole, are not rats...

[fatal]

its my 420th post and what better place to make it!

swim told me: good thing for weed otherwise i mightve never started shooting up meth and heroin! damn dealers pressuring me to escalate my drug use.

[enquirewithin]

“The issue of cross-sensitisation of cannabis/opioid receptors has been a controversial one, but these findings show the drug’s damaging effects on the reward structures of the brain,” van Oshe says. “There is now overwhelming evidence that nobody in the brain’s developmental stage – under the age of 21 – should use cannabis.”

Giving rats pure THC is not the same as humans smoking dope. What is the overwhelming evidence - or is it an overwhelming desire for a research grant?

[dnb warrior]

Some dub cannabis a “gateway” drug, arguing that peer pressure and exposure to drug dealers will tempt users to escalate their drug use. Others insist that smoking cannabis is unrelated to further drug use.

saying smoking cannabis is unrelated to further drug use is like saying learning to drive is unrelated to driving too fast and crashing. so what? also i think alcohol is as much a "gateway drug" as weed is.

as for this research involoving rats, i like the idea of some little pothead teenaged rat monged out in its cage, self administering heroin with a lever. but how do they know what dose of THC in rats is "roughly equivalent to a human smoking one joint every three days"? if there even is an equivalent?

[Nagognog2]

Not using marijuana seems to be connected with believing in Republican Presidents and a willingness to put on a uniform and shooting at strangers in foreign nations for unclear reasons.

All in all, I'd rather my chimp smoke pot and take the risk.

Reputation Comments on this post:

Always can find humor/irony in your posts.

[Kristy]

Rats self administering heroin?!! Thats a bizarre image....

[beentheredonethatagain]

[quote=Nagognog2;168618]Not using marijuana seems to be connected with believing in Republican Presidents and a willingness to put on a uniform and shooting at strangers in foreign nations for unclear reasons.

swim is a Republican, pot toker, meth graduate, ex- IV , pussy licking ,
conservative.
swim also thinks using aircraft as make shift missiles for downing skyscrapers,
is clear reason to shoot.
If it weren't for those brave Americans cloaked in our uniform, we would be singing the German or Jap national anthem

[enquirewithin]

[quote=beentheredonethatagain;279812]

Originally Posted by Nagognog2

Not using marijuana seems to be connected with believing in Republican Presidents and a willingness to put on a uniform and shooting at strangers in foreign nations for unclear reasons.

swim is a Republican, pot toker, meth graduate, ex- IV , pussy licking ,
conservative.
swim also thinks using aircraft as make shift missiles for downing skyscrapers,
is clear reason to shoot.
If it weren't for those brave Americans cloaked in our uniform, we would be singing the German or Jap national anthem

And your Republican heros want your ass in jail!

[Alicia]

Rats eeekkk!!
Once again...ah forget it. Maybe I should just have a txt file, a list of sentences which are warranted for these same recurring 'finds on cannabis'.
that i can paste in.
Im so tired with educating..

[Akewstick]

Rats self administering heroin?!! Thats a bizarre image....

i think it's more to do with rats standing on levers or opening doors, rather than giving them little rat-sized spoons and syringes, i could be wrong though

Reputation Comments on this post:

lol

[meRlin68]

is it true pot will mess up ur brain development?
cuz swim n his friends smoked since they were 12, and swim has definately seemed less smart and has a bad memory, although those may be temporary effects (swim hasnt gone more than a month without smoking in a while)

[jux]

Originally Posted by meRlin68

is it true pot will mess up ur brain development?
cuz swim n his friends smoked since they were 12, and swim has definately seemed less smart and has a bad memory, although those may be temporary effects (swim hasnt gone more than a month without smoking in a while)

Cannabis & Cognition
But what about claims of cannabis' damaging effect of cognition? A review of the scientific literature indicates that rumors regarding the "stoner stupid" stereotype are unfounded. According to clinical trial data published this past spring in the American Journal of Addictions, cannabis use -- including heavy, long-term use of the drug -- has, at most, only a negligible impact on cognition and memory. Researchers at Harvard Medical School performed magnetic resonance imaging on the brains of 22 long-term cannabis users (reporting a mean of 20,100 lifetime episodes of smoking) and 26 controls (subjects with no history of cannabis use). Imaging displayed "no significant differences" between heavy cannabis smokers compared to controls, the study found.
Previous trials tell a similar tale. An October 2004 study published in the journal Psychological Medicine examining the potential long-term residual effects of cannabis on cognition in monozygotic male twins reported "an absence of marked long-term residual effects of marijuana use on cognitive abilities." A 2003 meta-analysis published in the Journal of the International Neuropsychological Society also "failed to reveal a substantial, systematic effect of long-term, regular cannabis consumption on the neurocognitive functioning of users who were not acutely intoxicated," and a 2002 clinical trial published in the Canadian Medical Association Journal determined, "Marijuana does not have a long-term negative impact on global intelligence."
Finally, a 2001 study published in the journal Archives of General Psychiatry found that long-term cannabis smokers who abstained from the drug for one week "showed virtually no significant differences from control subjects (those who had smoked marijuana less than 50 times in their lives) on a battery of 10 neuropsychological tests." Investigators further added, "Former heavy users, who had consumed little or no cannabis in the three months before testing, [also] showed no significant differences from control subjects on any of these tests on any of the testing days."

i dont know if i can post a direct link to the article (are organizations like NORML considered commercial links?)

[jux]

the rest of the article....(since we are on the subject of marijuana and brain function)

Cannabis and the Brain: A User's Guide



by Paul Armento
Senior Policy Analyst
NORML | NORML Foundation

Preclinical data recently published in the Journal of Clinical Investigation demonstrating that cannabinoids may spur brain cell growth has reignited the international debate regarding the impact of marijuana on the brain. However, unlike previous pseudo-scientific campaigns that attempted to link pot smoking with a litany of cognitive abnormalities, modern research suggests what many cannabis enthusiasts have speculated all along: ganja is good for you.

Cannabinoids & Neurogenesis
"Study turns pot wisdom on its head," pronounced the Globe and Mail in October. News wires throughout North America and the world touted similar headlines -- all of which were met with a monumental silence from federal officials and law enforcement. Why all the fuss? Researchers at the University of Saskatchewan in Saskatoon found that the administration of synthetic cannabinoids in rats stimulated the proliferation of newborn neurons (nerve cells) in the hippocampus region of the brain and significantly reduced measures of anxiety and depression-like behavior. The results shocked researchers -- who noted that almost all other so-called "drugs of abuse," including alcohol and tobacco, decrease neurogenesis in adults -- and left the "pot kills brain cells" crowd with a platter of long-overdue egg on their faces.
While it would be premature to extrapolate the study's findings to humans, at a minimum, the data reinforce the notion that cannabinoids are unusually non-toxic to the brain and that even long-term use of marijuana likely represents little risk to brain function. The findings also offer further evidence that cannabinoids can play a role in the alleviation of depression and anxiety, and that cannabis-based medicines may one day offer a safer alternative to conventional anti-depressant pharmaceuticals such as Paxil and Prozac.
(Reference: Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic and depressant-like effects. The Journal of Clinical Investigation. 2005)

Cannabis & Neuroprotection
Not only has modern science refuted the notion that marijuana is neurotoxic, recent scientific discoveries have indicated that cannabinoids are, in fact, neuroprotective, particularly against alcohol-induced brain damage. In a recent preclinical study -- the irony of which is obvious to anyone who reads it -- researchers at the US National Institutes of Mental Health (NIMH) reported that the administration of the non-psychoactive cannabinoid cannabidiol (CBD) reduced ethanol-induced cell death in the brain by up to 60 percent. "This study provides the first demonstration of CBD as an in vivo neuroprotectant ... in preventing binge ethanol-induced brain injury," the study's authors wrote in the May 2005 issue of the Journal of Pharmacology and Experimental Therapeutics. Alcohol poisoning is linked to hundreds of preventable deaths each year in the United States, according to the Centers for Disease Control, while cannabis cannot cause death by overdose.
Of course, many US neurologists have known about cannabis' neuroprotective prowess for years. NIMH scientists in 1998 first touted the ability of natural cannabinoids to stave off the brain-damaging effects of stroke and acute head trauma. Similar findings were then replicated by investigators in the Netherlands and Italy and, most recently, by a Japanese research in 2005. However, attempts to measure the potential neuroprotective effects of synthetic cannabinoid-derived medications in humans have so far been inconclusive.
(References: Comparison of cannabidiol, antioxidants and diuretics in reversing binge ethanol-induced neurotoxicity. Journal of Pharmacology and Experimental Therapeutics. 2005 | Cannabidiol prevents cerebral infarction. Stroke. 2005 | Post-ischemic treatment with cannabidiol prevents electroencephalographic flattening, hyperlocomotion and neuronal injury in gerbils. Neuroscience Letters. 2003 | Neuroprotection by Delta9-tetrahydrocannabinol, the main active compound in marijuana, against ouabain-induced in vivo excitotoxicity. Journal of Neuroscience. 2001 | Cannabidiol and Delta9-tetrahydrocannabinol are neuroprotective antioxidants. Proceedings of the National Academy of Sciences. 1998)

Cannabinoids & Glioma
Of all cancers, few are as aggressive and deadly as glioma. Glioma tumors quickly invade healthy brain tissue and are typically unresponsive to surgery and standard medical treatments. One agent they do respond to is cannabis.
Writing in the August 2005 issue of the Journal of Neurooncology, investigators at the California Pacific Medical Center Research Institute reported that the administration of THC on human glioblastoma multiforme cell lines decreased the proliferation of malignant cells and induced apoptosis (programmed cell death) more rapidly than did the administration of the synthetic cannabis receptor agonist, WIN-55,212-2. Researchers also noted that THC selectively targeted malignant cells while ignoring healthy ones in a more profound manner than the synthetic alternative. Patients diagnosed with glioblastoma multiforme typically die within three months without therapy.
Previous research conducted in Italy has also demonstrated the capacity of CBD to inhibit the growth of glioma cells both in vitro (e.g., a petri dish) and in animals in a dose dependent manner. As a result, a Spanish research team is currently investigating whether the intracranial administration of cannabinoids can prolong the lives of patients diagnosed with inoperable brain cancer.
Most recently, a scientific analysis in the October issue of the journal Mini-Reviews in Medicinal Chemistry noted that, in addition to THC and CBD's brain cancer-fighting ability, studies have also shown cannabinoids to halt the progression of lung carcinoma, leukemia, skin carcinoma, colectoral cancer, prostate cancer and breast cancer.
(References: Cannabinoids selectively inhibit proliferation and induce cell death of cultured human glioblastoma multiforme cells. Journal of Neurooncology. 2005 | Cannabinoids and cancer. Mini-Reviews in Medicinal Chemistry. 2005 | Anti-tumor effects of cannabidiol, a non-psychotropic cannabinoid, on human glioma cell lines. Journal of Pharmacology and Experimental Therapeutics. 2003)

Cannabinoids & Neurodegeneration
Emerging evidence also indicates that cannabinoids may play a role in slowing the progression of certain neurodegenerative diseases, such as Multiple Sclerosis, Parkinson's disease, Alzheimer's, and Amyotrophic Lateral Sclerosis (a.k.a. Lou Gehrig's Disease). Recent animal studies have shown cannabinoids to delay disease progression and inhibit neurodegeneration in mouse models of ALS, Parkinson's, and MS. As a result, the Journal of Neurological Sciences recently pronounced, "There is accumulating evidence ... to support the hypothesis that the cannabinoid system can limit the neurodegenerative processes that drive progressive disease," and patient trials investigating whether the use of oral THC and cannabis extracts may slow the progression of MS are now underway in the United Kingdom.
(References: Cannabinoids and neuroprotection in CNS inflammatory disease. Journal of the Neurological Sciences. 2005. Amyotrophic lateral sclerosis: delayed disease progression in mice by treatment with a cannabinoid. Amyotrophic Lateral Sclerosis and Other Motor Neuron Disorders. 2004 | Cannabinoids inhibit neurodegeneration in models of multiple sclerosis. Brain. 2003)

Reputation Comments on this post:

	Now that's just fantastic! Great posting! :)
	Great post indeed

[Nagognog2]

What ever happened to the "Proven Research Study" that adolescent boys who smoked pot would definetly develop female breasts? It was a cock-sure thing! Steamer-trunks full of absolutely pure, irrefutable scientific tests! Where oh where did that go? It was an unshakable certainty from big-name Universitys with more Phd's attached than you shake a prick at!

Darn! Darn! Darn! Well back to square one:

MARIJUANA TURNS BOYS GAY AND GETS THEM PREGNANT! REALLY! WE'RE SURE THIS TIME! HONEST!

[Frivolous248]

http://www.scienceblog.com/cms/study...rug-12116.html

a 12 year study seems to think otherwise.

[meRlin68]

dude cmon im not reading that whole article, just tell swim yes or no

[jux]

Originally Posted by meRlin68

dude cmon im not reading that whole article, just tell swim yes or no

there was only one paragraph to read (the one under where i quoted you) and the first three sentances give you your answer...

the rest of the article is just general information on marijuana's neurological effect (which is why it is in a seperate post)

[fnord]

huh,you got me convinced micklemouse,ill never smoke again,not that i have,swim on the other hand needs to go roll a fatty! after reading all that!

[radiometer]

One of my absolute favorite authors is Dale Pendell. I can only hope to know someone as wise as he at some point in life. I like this short entry in his chapter on Cannabis from the book Pharmako/Poeia:

How to Use:
If you are young, you have to learn to say no. If you are old, don't be afraid to say yes. (If you are in between, you are too busy working to get into much trouble of any kind.)

I think what he's pointing out here is that young people need to be a bit careful, because without life experience and having too much time on one's hands, it is easy to get excessively wrapped up in Cannabis as an ally if not a lifestyle, and one can waste some of their most potentially productive years in a haze. I know that SWIM did so to a certain extent in his mid to late 20's, and wishes he had been a bit more temperate as he would be quite a bit farther ahead in life right now.