From Chapter 4: Therapeutic Applications of Cannabidiol (CBD)
4.2 CBD: The Most Important Cannabinoid in Hemp

After THC, cannabidiol (CBD) is the second cannabinoid most often encountered in the varieties of drugs derived from hemp. In hemp with low levels of THC, CBD is often the most present 9 cannabinoid with concentrations in the order of 0.5 to 2% in the top third of the plant. For individuals who would like to use CBD for therapeutic purposes, it is possible to buy hemp to prepare CBD teas or extracts using the leaves and the flowers. The teas contain naturally small quantities of CBD while the tinctures or oil extracts from the flowers can contain large quantities.

4.3 Research on the Effects of CBD

The principal effects of CBD have, until now, only been demonstrated through animal experimentation. In rats there has been a lessening of disorders due to nerve injury or inflammation. In a research trial, CBD lessened inflammation in a mouse with multiple sclerosis by preventing the production of the chemical mediators transmitting the inflammation. CBD has an effect of protecting nerves because it captures free radicals better than vitamin C. CBD has lessened the seriousness of the effects of a mechanical attack on the sciatic nerve in young rats. It is antiepileptic, inhibits nausea, kills carcinogenic cells in the case of breast cancer and a few other cancers, and inhibits the accumulation of Prion proteins in the affected cells which could prevent mad cow disease (BSE). Also in animal experimentation, CBD has been seen to act as an antibacterial agent against certain dangerous germs (MRSA) that are highly resistant to antibiotics; in addition, it has shown evidence of lessening the risk of developing diabetes. In a trial at the University of Teramo, cannabidiol influenced the multiplication of skin cells, which also suggests a possible application of new therapies to fight skin diseases.

4.4 Inhibition of the Effects of THC

One of the first effects of CBD observed in the human being has been CBD’s ability to inhibit the effects of THC. At the beginning of the 1980s, a Brazilian study team noticed that administering orally 20 mg of THC and 40 mg of CBD induced distinctly fewer effects on the 10 mind than only 20 mg of THC. The influence on heart rate was also lessened. Today, it is recognized that CBD implements its effects on the brain in part by blocking the first cannabinoid receptor, which is the receptor stimulated by THC. Thus, it is not surprising that CBD counteracts certain effects of THC, such as an increase in appetite. Someone wishing to have his appetite stimulated could then be advised to ingest pure THC or one of the varieties of cannabis rich in THC instead of the cannabis extract Sativex, which contains both THC and CBD.

In a study from 2004, an oral ingestion of 15 mg of THC administered to a few volunteers in the evening around 10 pm heightened sleepiness in comparison with a placebo. But when the participants, on a different evening, were given 15 mg of THC and 15 mg of CBD at the same time, the sedative effect of the THC was weakened, allowing what was possibly a stimulating effect from the CBD to appear. However, in other studies, a sedative effect of CBD was observed. In my experience, this situation of contradictory effects is even more the case with CBD than with THC, thus with certain individuals the effect is sedative and with others it is stimulating.

4.5 Positive Effects on Anxiety Disorders

A study by the Brazilian study team mentioned above was published in 1993. It compares the soothing effects on anxiety disorders of 300 mg of cannabidiol and 10 mg of diazepam (Valium). Participants were asked to make a speech that was being filmed. This process increases subjective anxiety and its physiological side effects such as increased heart rate and breathing rate. The results showed that CBD and Diazepam lessened the anxiety induced by the test.

A trial conducted in the psychopharmacological clinic at the University of London suggests that CBD could be useful in treating post-traumatic stress syndrome (PTSD). In this study, which involved 48 participants who were in good health, the CBD reinforced the consolidation of the extinction of fear. Participants were told that following a neutral stimulus (a colored box), a second, more disagreeable stimulus (an electric shock) would happen. This was followed by a period when there was no longer a disagreeable stimulus following the neutral stimulus. During this period the fear of the second disagreeable stimulus was dissipated. CBD had a positive effect on forgetting this second event.

In 2013, scientists at the University of São Paulo sought to understand if CBD could be beneficial against dyskinesia and Parkinson’s disease. They found that CBD activates a particular receptor (5-HT1A) in the striatum, a region of the brain responsible for movement.

4.6 Antipsychotic Effects

In 1995, the same study team published the first experiments in using cannabidiol with a psychotic patient. The symptoms declined with a CBD treatment of 1500 mg per day. In a recent study at the University of Cologne antipsychotic effects were also shown with a daily dose of 800 mg.

4.7 The Fight against Various Types of Cancer

One of the most significant discoveries in recent years was that of the anticarcinogenic effects of cannabidiol. In 2006, Italian scientists found that cannabidiol inhibited the growth of human breast cancer cells that were injected under the skin of mice. The CBD also reduced pulmonary metastases that appeared in animals from human breast cancer cells. CBD led the cells to eliminate themselves. In 2013, an Italian research team reported inhibiting tumor effects with CBD in the case of a brain tumor (glioma). The same year scientists at St. George’s, University of London, reported that CBD (cannabidiol), cannabigerol (CBG), and cannabivarine (CBGV) acted against leukemic cells (blood cancer) and that this effect was more powerful if the cannabinoids being tested were administered together.