IACM-Bulletin of January 22, 2006

UK — Cannabis will not be reclassified

Home secretary Charles Clarke said on 19 January that cannabis would not be reclassified as a Class B drug again. While pledging to launch a public information campaign on the dangers of cannabis use, Mr Clarke said that reclassification had not led to an increase in use. He told members of parliament that he had been guided by a report by the Advisory Council on the Misuse of Drugs (ACMD).

David Blunkett, his predecessor as Home Secretary, downgraded cannabis from a Class B to a Class C drug. Concerns about a link between super-strength cannabis varieties and mental illness have mounted since the down-grading of the drug took effect in January 2004, making cannabis possession a non-arrestable offence in most cases.

Mr Clarke said that he will launch a major public information campaign to stress that cannabis was "anything but harmless". He also said that draft guidelines published in November which would have allowed people to carry up to half a kilogram of leaf cannabis for "personal use" will be altered. "I would like to inform the House that my final decision will be at a considerably lower threshold than the 500g suggested in the current consultation," he said. He announced a new initiative to arrest cannabis producers and dealers.

(Source: Times Online of 19 January 2006)

Science — Activation of CB2 receptor attenuates bone loss in osteoporosis

Researchers of the University of Jerusalem investigated the role of the CB2 receptor in bone formation and bone loss. Mice without CB2 receptors were shown to have a markedly accelerated age-related bone loss. These mice were also characterized by increased activity of osteoblasts (bone-forming cells) and increased osteoclast (the bone-resorbing cell) number. The CB2 receptor is found on osteoblasts, osteoclasts and bone cells (osteocytes).

A synthetic cannabinoid (HU-308) that binds specifically to CB2 receptors enhanced osteoblast number and activity and reduced the production of osteoclasts. The same cannabinoid attenuated bone loss induced by removal of the ovary and markedly stimulated bone formation. Researchers concluded that these results "demonstrate that the endocannabinoid system is essential for the maintenance of normal bone mass by osteoblastic and osteoclastic CB2 signaling. Hence, CB2 offers a molecular target for the diagnosis and treatment of osteoporosis, the most prevalent degenerative disease in developed countries."

(Source: Ofek O, Karsak M, Leclerc N, Fogel M, Frenkel B, Wright K, Tam J, Attar-Namdar M, Kram V, Shohami E, Mechoulam R, Zimmer A, Bab I. Peripheral cannabinoid receptor, CB2, regulates bone mass. Proc Natl Acad Sci U S A 2006;103(3):696-701)

USA — San Diego County sues the state of California for its medical cannabis law

On 20 January San Diego County filed a lawsuit in U.S. District Court in San Diego against the state of California that challenges a voter-approved California law allowing cannabis use for medical purposes. John Sansone, the county's top lawyer, said there was no word on when the courts might begin listening to arguments in the lawsuit. The lawsuit asks a federal judge to decide whether federal law outlawing cannabis use for any purpose trumps the state’s medical cannabis law that allows sick people to smoke cannabis. It asks the court to ban the enforcement of the Californian cannabis law.

The American Civil Liberties Union said on 18 January that it was drafting a letter to the county warning that it would intervene to force the county to follow the state's medical marijuana law, which was approved by 55 percent of the voters.

Most county voters support California's 9-year-old medical marijuana law and oppose San Diego County supervisors' plan to sue to overturn it, according to a survey released on 9 January. The telephone survey of 500 randomly selected county voters found that 67 per cent of respondents supported the Californian medical cannabis law. 70 per cent said the county should follow state law.

(Sources: North County Times of 10 and 21 January 2006, Associated Press of 19 January 2006)

Science — THC effective against side effects of chemotherapy resistant to standard antiemetic therapy

Researchers of the University of Goettingen, Germany, treated 7 patients who suffered from malignant skin tumours (melanoma with liver metastases) with THC (dronabinol). All patients had received standard antiemetic therapy previously without adequate relief.

The majority of patients described a significant increase in appetite and decrease in nausea. These effects pertained for several weeks, and then decreased as disease progressed and general condition worsened. All patients experienced mild to moderate dizziness, which did not cause them to interrupt or stop the treatment with THC. Researchers concluded that "loss of appetite and nausea due to liver metastases of malignant melanoma can be treated in individual cases" with THC.

(Source: Zutt M, Hanssle H, Emmert S, Neumann C, Kretschmer L. Dronabinol zur supportiven Therapie metastasierter maligner Melanome mit Lebermetastasen. Hautarzt. 2006 Jan 12; [electronic publication ahead of print])

News in brief

Science — Nausea in pregnancy

A survey was conducted in Canada among pregnant women who used cannabis to treat nausea and vomiting. 59 of the participants had experienced nausea and/or vomiting during pregnancy. 40 had used cannabis to treat this condition and of these 37 (92.5%)

rated cannabis as extremely effective or effective. (Source: Westfall RE, et al. Complement Ther Clin Pract. 2006 Feb;12(1):27-33)

Science — Colon inflammation

Inhibitors of anandamide degradation or re-uptake were shown to reduce colon inflammation in mice and rats. The animals were treated for 3 or 7 days with one of the agents. Re-uptake inhibitors were shown to be much more effective than an inhibitor of anandamide degradation. The compounds applied in the animal studies also increased anandamide levels in tissue samples of patients with ulcerative colitis (Colitis ulcerosa). (Source: D'Argenio G, et al. FASEB J. 2006 Jan 10; [electronic publication ahead of print])

Science — Memory

In this study rats were trained to associate a tone with an electric footshock. Earlier observations were confirmed that cannabinoids accelerate the extinction of unpleasant memories. This effect was mediated by the CB1 receptor. (Source: Pamplona FA, Takahashi RN. Neurosci Lett. 2006 Jan 4; [electronic publication ahead of print])

Science — Schizophrenia

Cannabidiol was uneffective in 3 patients who suffered from treatment-resistant schizophrenia. All patients were given placebo for the initial 5 days, and from the 6th to 35th day they received CBD (initial oral dose of 40 mg reaching 1280 mg/day). On day 36th, CBD treatment was discontinued and replaced by placebo for 5 days, which was subsequently switched to the anti-psychotic olanzapine for over 15 days. One patient showed mild improvement, but two patients didn't show any improvement during CBD monotherapy. (Source: Zuardi AW, et al. J Psychopharmacol 2006 Jan 9; [electronic publication ahead of print])