Cannabis has been promoted in the United States over the last 20 years as a means of relieving a wide range of conditions. It is said to provide relief for chronic states of pain, loss of appetite in the case of aids patients and cancer sufferers, nausea and vomiting (as a result of chemotherapy), asthma, glaucoma (increased internal pressure on the eye) and for sufferers of multiple sclerosis. Many marijuana users report that their symptoms are relieved, and that smoking this substance confers a feeling of well-being. As a result of referendum decisions, doctors in ten US states can now prescribe marijuana as a medicine.

But various questions remain unanswered:

• Is cannabis really effective?

• Do we really take into account the cancer risk produced by smoking parts of a dried plant that contains hundreds of chemical substances, some of which are classed as carcinogenic?

• Should we not wait until the active ingredient becomes available in a pure form, for administration by tablet or as drops?

• What about the side-effects?

• The main question is: Does cannabis fulfill the strict official guidelines on what constitutes an approved medical drug?

Cannabinoids

The terms “cannabis” and “marijuana” refer to the dried, unfertilized female flowers and leaves of the Indian hemp plant. The narcotic effect of the hemp plant is obtained from the 60 cannabinoids that it contains, particularly delta-9-tetrahydrocannabinol (THC), its biological precursor cannabidiol (CBD) and the THC decomposition product cannabinol (CBN). These substances stimulate the cannabinoid receptors in the central nervous system of the organism. The body’s on-board (endogenous) triggers for these receptors are called endocannabinoids, which play an important role in the modulation of many neuronal processes.

Endogenous Cannabinoids

Human cannabis receptors CB1 and CB2 were discovered only 15 years ago. The human body possesses more CB1 receptors than dopamine, serotonin and noradrenaline. The endogenous substance that docks with these receptors to make them effective is anandamide. The role of anandamide receptor systems in the human body continues to be unclear.

The largest numbers of CB1 receptors, to which anandamide and THC attach themselves, are found in the brain. CB1 receptors are located above all in the frontal lobes (responsible motivation, planning) and in the basal ganglia and cerebellum (responsible for movement, coordination). In the limbic system, these receptors are present above all in the hypothalamus (regulation of food intake and body weight). Many of these receptors are also present in the hippocampus (memory). Their relatively low presence in the brain stem, from where the respiratory system is controlled, explains why it is not possible to die from an overdose of cannabinoids.

CB2 receptors are distributed around most of the body’s organs, with high concentrations in the spleen, the testicles and the immune cells.