RECENT STUDIES

Recent studies

Safety of cannabis

According to an approved statement from the US Department of Justice in 1988, “Nearly all medicines have toxic, potentially lethal effects. But cannabis is not such a substance. There is no record in the extensive medical literature describing a proven, documented cannabis-induced fatality. In practical terms, cannabis cannot induce a lethal response as a result of drug-related toxicity.”^[53]

From January 1997 to June 2005, the U.S. Food and Drug Administration (FDA) reported zero deaths caused by the primary use of cannabis. In contrast, common FDA-approved drugs which are often prescribed in lieu of cannabis (such as anti-emetics and anti-psychotics), were the primary cause of 10,008 deaths.^[54] The cannabinoid THC has an extremely low toxicity and the amount that can enter the body through the consumption of cannabis plants poses no threat of death.^[55]

Cannabis smoke contains substances that can damage DNA and increase the risk of cancer just like tobacco smoke, though no definitive link between cannabis and cancer has been found.^[56] Cancer causing chemicals in cannabis smoke have been found in amounts 50% higher than those found in tobacco smoke. According to the British Lung Foundation, smoking three to four joints (cannabis cigarettes) a day has been found to be associated with the same degree of damage to tissue in the airways of the lung as 20 or more tobacco cigarettes a day.^[57]

The Journal of the American Medical Association released findings from a 20-year study that bolstered evidence that cannabis doesn’t do the kind of damage tobacco does. Analysis of over 5,000 smokers showed that cannabis did not appear to harm lung function, although cigarettes did. Cigarette smokers’ scores worsened steadily over the course of the study. Participants who smoked up to 1 joint daily for 7 years, or 1 joint weekly for 20 years, were not linked with worse scores. Dr Donald Tashkin suggested the reason for this might be that cannabis helps fight inflammation and may counteract the effects of irritating chemicals in  the drug.^[56]The study concluded: “Occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function”.^[58]

Cannabis usage has been shown to negatively affect the ability to drive safely.^[59] The British Medical Journal recently indicated that “Drivers who consume cannabis within three hours of driving are nearly twice as likely to cause a vehicle collision as those who are not under the influence of drugs or alcohol”^[60]

Glaucoma

In glaucoma, cannabis and THC have been shown to reduce intra-ocular pressure (IOP) by an average of 24% in people with normal IOP who have visual-field changes. In studies of healthy adults and glaucoma patients, IOP was reduced by an average of 25% after smoking a cannabis “cigarette” that contained approximately 2% THC—a reduction as good as that observed with most other medications available today, according to a review by the Institute of Medicine.^[61]

In a separate study, the use of cannabis and glaucoma was tested and found that the duration of smoked or ingested cannabis or other cannabinoids is very short, averaging 3 to 3.5 hours. Their results showed that for cannabis to be a viable therapy, the patient would have to take in cannabis in some form every 3 hours. They said that for ideal glaucoma treatment it would take two times a day at most for compliance purposes from patients.^[62]

Spasticity in multiple sclerosis

A review of six randomized controlled trials of a combination of THC and CBD extracts for the treatment of multiple sclerosis (MS) related muscle spasticity reported, “Although there was variation in the outcome measures reported in these studies, a trend of reduced spasticity in treated patients was noted.” The authors postulated that “cannabinoids may provide neuroprotective and anti-inflammatory benefits in MS.”^[63] A small study done on whether or not cannabis could be used to control tremors of MS patients was conducted. The study found that there was no noticeable difference of the tremors in the patients. Although there was no difference in the tremors the patients felt as if their symptoms had lessened and their quality of life had improved. The researchers concluded that the mood enhancing or cognitive effects that cannabis has on the brain could have given the patients the effect that their tremors were getting better.^[64][65]

Alzheimer’s disease

Research done by the Scripps Research Institute in California shows that the active ingredient in marijuana, THC, prevents the formation of deposits in the brain associated with Alzheimer’s disease. THC was found to prevent an enzyme called acetylcholinesterase from accelerating the formation of “Alzheimer plaques” in the brain more effectively than commercially marketed drugs. THC is also more effective at blocking clumps of protein that can inhibit memory and cognition in Alzheimer’s patients, as reported in Molecular Pharmaceutics.^[66] Cannabinoids can also potentially prevent or slow the progression of Alzheimer’s disease by reducing tau protein phosphorylation, oxidative stress, and neuroinflammation.^[67]

Breast cancer

According to a 2007 study at the California Pacific Medical Center Research Institute, cannabidiol (CBD) may stop breast cancer from spreading throughout the body.^[68] These researchers believe their discovery may provide a non-toxic alternative to chemotherapy while achieving the same results minus the painful and unpleasant side effects. The research team says that CBD works by blocking the activity of a gene called Id-1, which is believed to be responsible for a process called metastasis, which is the aggressive spread of cancer cells away from the original tumor site.^[68]

HIV/AIDS

Investigators at Columbia University published clinical trial data in 2007 showing that HIV/AIDS patients who inhaled cannabis four times daily experienced substantial increases in food intake with little evidence of discomfort and no impairment of cognitive performance. They concluded that smoked cannabis has a clear medical benefit in HIV-positive patients.^[69][70] In another study in 2008, researchers at the University of California, San Diego School of Medicine found that marijuana significantly reduces HIV-related neuropathic pain when added to a patient’s already-prescribed pain management regimen and may be an “effective option for pain relief” in those whose pain is not controlled with current medications. Mood disturbance, physical disability, and quality of life all improved significantly during study treatment.^[71] Despite management with opioids and other pain modifying therapies, neuropathic pain continues to reduce the quality of life and daily functioning in HIV-infected individuals. Cannabinoid receptors in the central and peripheral nervous systems have been shown to modulate pain perception. No serious adverse effects were reported, according to the study published by the American Academy of Neurology.^[72] A study examining the effectiveness of different drugs for HIV associated neuropathic pain found that smoked Cannabis was one of only three drugs that showed evidence of efficacy.^[73]

Brain cancer

A study by Complutense University of Madrid found the chemicals in cannabis promote the death of brain cancer cells by essentially helping them feed upon themselves in a process called autophagy. The research team discovered that cannabinoids such as THC had anticancer effects in mice with human brain cancer cells and in people with brain tumors. When mice with the human brain cancer cells received the THC, the tumor shrank. Using electron microscopes to analyze brain tissue taken both before and after a 26- to 30-day THC treatment regimen, the researchers found that THC eliminated cancer cells while leaving healthy cells intact.^[74] The patients did not have any toxic effects from the treatment; previous studies of THC for the treatment of cancer have also found the therapy to be well tolerated. However, the mechanisms which promote THC’s tumor cell–killing action are unknown.^[74]

Opioid dependence

Injections of THC eliminate dependence on opiates in stressed rats, according to a research team at the Laboratory for Physiopathology of Diseases of the Central Nervous System (France) in the journalNeuropsychopharmacology.^[75] Deprived of their mothers at birth, rats become hypersensitive to the rewarding effect of morphine and heroin (substances belonging to the opiate family), and rapidly become dependent. When these rats were administered THC, they no longer developed typical morphine-dependent behavior. In the striatum, a region of the brain involved in drug dependence, the production of endogenous enkephalins was restored under THC, whereas it diminished in rats stressed from birth which had not received THC. Researchers believe the findings could lead to therapeutic alternatives to existing substitution treatments.^[75]

In humans, drug treatment subjects who use cannabis intermittently are found to be more likely to adhere to treatment for opioid dependence.^[76] Historically, similar findings were reported by Edward Birch, who, in 1889, reported success in treating opiate and chloral addiction with cannabis.^[77]

Controlling ALS symptoms

Recent research has been conducted on if the use of cannabis could control some of the symptoms of ALS or Lou Gehrig’s Disease. A survey was conducted on 131 people who suffered from ALS. The survey asked if the subjects had used cannabis in the last 12 months to control some of their symptoms. The survey resulted in 13 people who had used the drug in some form to control symptoms. The survey results found that cannabis was moderately effective in reducing symptoms of appetite loss, depression, pain, spasticity, drooling and weakness and the longest relief reported was for depression. The pattern of symptom relief was consistent with those reported by people with other conditions, including multiple sclerosis (Amtmann et al. 2004).^[64]