IACM-Bulletin of September 30, 2007

Science — THC normalized impaired psychomotor performance and mood in a patient with hyperactivity disorder

Scientists at the Department for Forensic and Traffic Medicine of the University of Heidelberg, Germany, investigated the effects of cannabis on driving related functions in a 28 year old man with attention-deficit/hyperactivity disorder (ADHD). He had violated traffic regulations several times in recent years and his driving licence was revoked due to driving under the influence of cannabis. He showed abnormal behaviour, seemed to be significantly maladjusted and his concentration was heavily impaired while sober during the first meeting with a psychologist. He was allowed to perform driving related tests under the influence of the cannabis compound dronabinol (THC), which his doctor had prescribed him to treat his symptoms. The examiner expected that he was not able to drive a car under the acute influence of THC.

But at the second visit his behaviour was markedly improved and he performed average and partly above-average in all tests on reaction speed, sustained attention, visual orientation, perception speed and divided attention. A blood sample taken after the tests revealed a high THC concentration of 71 ng/ml in blood serum. He admitted later to have smoked cannabis and not taken dronabinol, because it was too expensive. Researchers noted that "people with ADHD are found to violate traffic regulations, to commit criminal offences and to be involved in traffic accidents more often than the statistical norm" and conclude from their investigation that "it has to be taken into account that in persons with ADHD THC may have atypical and even performance-enhancing effects."

(Source: Strohbeck-Kuehner P, Skopp G, Mattern R. Fahrtüchtigkeit trotz (wegen) THC. [Fitness to drive in spite (because) of THC] [Article in German] Arch Kriminol 2007;220(1-2):11-9.)

USA — The state of Washington tries to define a standard dosage for cannabis

According to the medical cannabis law of the state of Washington qualified patients may possess up to a 60-day supply of cannabis. Now the state legislature wants to know how much that is, since there is no standard dose and no standard method to use cannabis medicinally. Therefore the state is holding hearings to ask experts and citizens for their opinions on how to determine a two-month supply. Currently in each county, law enforcement effectively decides what constitutes a 60-day supply.

Of the 12 states that protect medical cannabis patients from state prosecution, Washington is the only one without clear guidelines on the amount a patient or designated caregiver is allowed to possess. Oregon allows the largest supply – 24 ounces (about 680 grams) or six mature plants – and several states only allow patients to have one ounce (about 28 grams) of usable cannabis on hand. In California, state law sets a limit of 8 ounces or six mature plants, but cities and counties are free to establish higher guidelines. There are fears among patients in Washington that the state might set the limit too low. Public comments on the issue will be accepted until the end of the year, and in early 2008, the department of health will publish a proposed rule.

(Source: Los Angeles Times of 23 September 2007)

News in brief

Science — Heart protection

According to a study of researchers of the Hebrew University in Jerusalem the non-psychoactive cannabinoid cannabidiol (CBD) protected the heart against damage by reduced blood supply in an animal study. A heart artery was ligated in rats for 30 minutes. In animals treated thereafter for 7 days with CBD infarct size was reduced by 66 per cent compared to non-treated rats. (Source: Durst R, et al. Am J Physiol Heart Circ Physiol. 2007 Sep 21; [Electronic publication ahead of print])

Science — Schizophrenia

Researchers at the Medical School of Hannover investigated in 104 patients with schizophrenia and 140 healthy controls, if mutations in the cannabinoid-1 receptor was associated with an increased risk for schizophrenia. Such an association was not detected. (Source: Seifert J, et al. Neurosci Lett. 2007 Aug 10; [Electronic publication ahead of print])

Science — New cannabinoid receptor

According to researchers of the pharmaceutical company AstraZeneca there is now sufficient evidence that the receptor GPR55 is a novel cannabinoid receptor. Among the substances that bind to this receptor are the endocannabinoids anandamide and virodhamine, the phytocannabinoid cannabidiol and the synthetic cannabinoids CP55940 and abnormal cannabidiol. (Source: Ryberg E, et al. Br J Pharmacol. 2007 Sep 17; [Electronic publication ahead of print])