Mary Brett … a cause for concern.

Well it’s been some time comin,g but now feels about the right time to look at some of the ‘scientific’ information that talking about cannabis plan to distribute to schools and parents.  On the Talking About Cannabis website parents and children are invited to download a document written by one Mary Brett, spokesperson for Europe Against Drugs (EURAD … and we’re getting round to them).

Unfortunately facts seem in fairly short supply in this document. You really can’t blame poor old Brett, no matter how often she dishonestly refers to herself as a biologist her lowly BSc and career in an all boys Grammar School clearly marks her down as a teacher … and if her ability to construct a legible sentence is anything to go by then perhaps not a very good one.

Brett’s trick is to trawl through scientific studies of varying legitamacy and then present as fact results which even the original researchers ackowledge are as yet unproven.

Any studies which disagree with Brett’s opinion are studiously ignored, which is a shame for her because most studies do tend to disagree with Brett’s biased conculsions.

Let’s start with a quote from the Lancet (real scientists) who in an editorial in 1995 said:

The smoking of cannabis, even long term, is not harmful to health.”

Whilst the possibility that cannabis may have some link to psychosis remains an, as yet unproven concern, the scientific consensus regarding the physical risks of cannabis remain much the same as stated in the above editorial.

That doesn’t stop Brett though who claims:

“Just one joint per week will ensure a permanent presence of THC. Functioning of all the other neurotransmitters is affected New nerve connections cannot be made
Concentration, learning and memory are all badly affected.

There is now strong suggestive evidence from animal experiments and brain scans of humans that some of these cells may die. “

So let’s have the facts. The myth that cannabis kills brain cells is largely down to one study in the 1970’s in which three Rhesus monkeys were heavily dosed with cannabis and structural changes (not cell death) in the brain were observed.

This study was heavily criticised at the time and the results have never been replicated. Much larger monkey studies, one by Dr. William Slikker of the National Center for Toxicological Research (1) and the other by Charles Rebert and Gordon Pryor of SRI International(2),  failed to any evidence of physical alteration in the brains of monkeys exposed to daily doses of cannabis for up to a year.

Human studies of heavy users in Jamaica and Costa Rica also found no evidence of abnormalities in brain physiology (3).

So Brett’s claim that cannabis causes:

“permanent brain damage – slow, subtle, insidious and cumulative.”

and that

“Few children, using cannabis even occasionally, will achieve their full potential.”

have no actual basis in fact whatsoever. Anyone would think she had an agenda.

Brett also gets very upset over the fact that THC is fat soluble (like many substances) and therefore tends to hang about in the body for some time. Brett claims:

“Airline pilots on flight simulators could not ‘land’ their planes properly even 24 hours and more after a joint”

As ever the truth is far less dramatic. Presumably Brett is referring to a pair of flight simulator studies by Leirer, Yesavage, and Morrow, which reported effects on a flight simulator performance up to 24 hours after using cannabis. (4)

Whilst the study did find some impact on pilot’s performance Leirer himself said the effects were “very subtle” and “very marginal,” and were less than those noted due to pilots ages.

A later flight simulator study by the same group failed to find any effects beyond 4 hours after using cannabis. (5)

So once again Brett has twisted the facts to suit her own agenda.

Onto the issue of whether cannabis is addictive Brett claims:

“More young people treated in the USA for marijuana than alcohol dependence”

What Brett fails to mention is that at least half of all young people in the US are in treatment programmes for cannabis due to court orders. It should also be noted that many parents and schools who listen to the hysterical ramblings of the likes of Brett may refer their children into treatment regardless of whether they have a problem.

Brett claims that physical dependance to cannabis is not as severe as heroin addiction because THC stored in the body reduces the severity of withdrawal symptoms.

Which frankly, is fucking nonsense.

There is no compulsive scientific evidence that cannabis can cause physical dependance. The study “Clinical Studies of Cannabis Tolerance and Dependence,” concluded that:

“When human subjects were administered daily oral doses of 180-210 mg of THC – the equivalent of 15-20 joints per day – abrupt cessation produced adverse symptoms, including disturbed sleep, restlessness, nausea, decreased appetite, and sweating.

The authors interpreted these symptoms as evidence of physical dependence. However, they noted the syndrome’s relatively mild nature and remained skeptical of its occurrence when marijuana is consumed in usual doses and situations.” ⁽⁶⁾

Evidence has also been presented that suggests when humans are allowed to control consumption, even high doses are not followed by adverse withdrawal symptoms.(7)

Meanwhile national epidemiological surveys in the US show that the large majority of people who use cannabis do not become regular users.

In 1993, among Americans age 12 and over, about 34% had used marijuana sometime in their life, but only 9% had used it in the past year, 4.3% in the past month, and 2.8% in the past week. (8)

So once again Brett’s scare-mongering fails to match up to the scientific evidence.

The effect of cannabis on mental health is too large an issue for the scope of this document. We will note that the debate is not helped by Brett’s claim that:

“Cannabis increases the amount of the neurotransmitter, dopamine in the brain.
Too much dopamine causes schizophrenia.”

The dopamine theory of schizophrenia is just that, a theory – not a fact. It has largely been discredited as far too simplistic an approach and in any event the idea that cannabis causes an increase of dopamine in the brain has not been established beyond doubt.

Sex, shopping and chocolate all cause an increase of dopamine in the brain.

As for Brett’s comment that:

“Even on one joint per month or six weeks, a cannabis personality emerges.”

Which presumably is something that she just made up ‘cos it sounded good, long live the Brett school of science.

And finally Brett chucks in a few hand-grenades at the end claiming that cannabis causes head and neck cancers, the immune system is damaged and that babies born to cannabis using mothers are smaller, hyperactive and have behaviour and learning problems .

With regard to her claim that young people who smoke are developing head and neck cancers, the truth of this unfounded allegation can be found on EURAD’s own website:

“in a cohort study with 8 years of follow-up, marijuana use was not associated with increased risks of all cancers or smoking-related cancers. Further epidemiological studies are necessary to confirm the association of marijuana smoking with head and neck cancers and to examine marijuana smoking as a risk factor for lung cancer. ” (9)

The research which has been carried out suggesting cannabis may damage the immune system has typically involved lab animals being given huge doses of THC. According to a review on the subject by Dr. Leo Hollister(10):

“The evidence [on immune suppression] has been contradictory and is more supportive of some degree of immunosuppression only when one considers in vitro studies. These have been seriously flawed by the very high concentrations of drug used to produce immunosuppression. The closer that experimental studies have been to actual clinical situations, the less compelling has been the evidence.”

Once again Brett produces scant evidence as scientific fact.

And as to a risk to unborn babies, once again the evidence is far from conclusive with one study suggesting that cannabis use had a positive impact on birthweight during the third trimester of pregnancy with no adverse behavioral consequences.(11)

A further study of Jamaican women who had used cannabis throughout pregnancy found that their babies registered higher on developmental scores at 30 days, whilst experiencing no significant effects on birthweight or length. (12)

Finally Brett seeks to simplify and discredit medical cannabis with the dramatic claim that cannabis contains over 400 chemicals.

Brewed coffee contains around 800.

The rest of Brett’s leaflet contains brief details on the effects of other drugs, which although in some cases are not entirely accurate, they are not covered in anywhere near the same detail as cannabis.

Brett and her cohorts may wish to consider what the kids will make of this info after being subjected to a diatribe of dishonest and unscientific drivel on the subject of cannabis.

And those MP’s and charities which have offered Talking About Cannabis support may wish to consider whether they really support lying to young people about drugs.

Net-savvy teenagers can easily find all of the information presented above.

Are they likely to believe anything they are told about drugs at all if this kind of malicious propaganda becomes the norm in schools?

(1) William Slikker et al., Chronic Marijuana Smoke Exposure in the Rhesus Monkey, Fundamental and Applied Toxicology 17: 321-32 (1991).
(2) Charles Rebert & Gordon Pryor – Chronic Inhalation of Marijuana Smoke and Brain Electrophysiology of Rhesus Monkeys, International Journal of Psychophysiology V 14, p.144, 1993.
(3) NATIONAL ACADEMY OF SCIENCES Report, pp. 82-7.
(4) V.O. Leirer, J.A. Yesavage and D.G. Morrow, “Marijuana Carry-Over Effects on Aircraft Pilot Performance,” Aviation Space and Environmental Medicine 62: 221-7 (March 1991); Yesavage, Leirer, et al., “Carry-Over effects of marijuana intoxication on aircraft pilot performance: a preliminary report,” American Journal of Psychiatry 142: 1325-9 (1985).
(5) Leirer, Yesavage and Morrow, “Marijuana, Aging and Task Difficulty Effects on Pilot Performance,” Aviation Space and Environmental Medicine 60: 1145-52 (Dec. 1989).
(6) Jones, R.T. et al, “Clinical Studies of Cannabis Tolerance and Dependence,” Annals of the New York Academy of Sciences 282:221-39 (1976).
(7) Stefanis. C. et al, “Experimental Observations of a 3-Day Hashish Abstinence Period and Reintroduction of Use,” Annals of the New York Academy of Sciences 282:113-20 (1976); Cohen, S. et al, “The 94-Day Study,” pp 621-26 in M.C. Braude and S. Szara (eds), The Pharmacology of Marijuana, New York: Raven Press (1976).
(8) Preliminary Estimates from the 1993 National Household Survey on Drug Abuse, Rockville, MD: U.S. Department of Health and Human Services (1994).
(9) Journal of Clinical Pharmacology, 2002;42:103S-107S
(10) Dr. Leo Hollister, Marijuana and Immunity, Journal of Psychoactive Drugs 20(1): 3-8 (Jan/Mar 1988).
(11) Nancy Day et al., Prenatal Marijuana Use and Neonatal Outcome, Neurotoxicology and Teratology 13: 329-34 (1992).
(12) Janice Hayes, Melanie Dreher and J. Kevin Nugent, Newborn Outcomes With Maternal Marihuana Use in Jamaican Women, Pediatric Nursing 14 #2: 107-10 (Mar-Apr. 1988).