Over of Alzheimer's research from NORML website

Alzheimer's Disease

Join the Discussion

Alzheimer’s disease (AD) is a neurological disorder of unknown origin that is characterized by a progressive loss of memory and learned behavior. Patients with Alzheimer’s are also likely to experience depression, agitation, and appetite loss, among other symptoms. Over 4.5 million Americans are estimated to be afflicted with the disease. No approved treatments or medications are available to stop the progression of AD, and few pharmaceuticals have been FDA-approved to treat symptoms of the disease.

A review of the recent scientific literature indicates that cannabinoid therapy may provide symptomatic relief to patients afflicted with AD while also moderating the progression of the disease.

Writing in the February 2005 issue of the Journal of Neuroscience, investigators at Madrid's Complutense University and the Cajal Institute in Spain reported that the intracerebroventricular administration of the synthetic cannabinoid WIN 55,212-2 prevented cognitive impairment and decreased neurotoxicity in rats injected with amyloid-beta peptide (a protein believed to induce Alzheimer’s). Additional cannabinoids were also found to reduce the inflammation associated with Alzheimer's disease in human brain tissue in culture. "Our results indicate that … cannabinoids succeed in preventing the neurodegenerative process occurring in the disease," investigators concluded.[1]

More recently, investigators at The Scripps Research Institute in California reported that THC inhibits the enzyme responsible for the aggregation of amyloid plaque — the primary marker for Alzheimer's disease — in a manner "considerably superior" to approved Alzheimer's drugs such as donepezil and tacrine. "Our results provide a mechanism whereby the THC molecule can directly impact Alzheimer's disease pathology," researchers concluded. "THC and its analogues may provide an improved therapeutic [option] for Alzheimer's disease [by]... simultaneously treating both the symptoms and the progression of [the] disease."[2]

Previous preclinical studies have demonstrated that cannabinoids can prevent cell death by anti-oxidation.[3] Some experts believe that cannabinoids’ neuroprotective properties could also play a role in moderating AD.[4]

In addition to potentially modifying the progression of AD, clinical trials also indicate that cannabinoid therapy can reduce agitation and stimulate weight gain in patients with the disease. Most recently, investigators at Berlin Germany’s Charite Universitatmedizin, Department of Psychiatry and Psychotherapy, reported that the daily administration of 2.5 mg of synthetic THC over a two-week period reduced nocturnal motor activity and agitation in AD patients in an open-label pilot study.[5]

Clinical data presented at the 2003 annual meeting of the International Psychogeriatric Association previously reported that the oral administration of up to 10 mg of synthetic THC reduced agitation and stimulated weight gain in late-stage Alzheimer’s patients in an open-label clinical trial.[6] Improved weight gain and a decrease in negative feelings among AD patients administered cannabinoids were previously reported by investigators in the International Journal of Geriatric Psychiatry in 1997.[7] Additional study of the use of cannabinoids and Alzheimer’s would appear to be warranted.

REFERENCES

[1] Ramirez et al. 2005. Prevention of Alzheimer’s Disease pathology by cannabinoids. The Journal of Neuroscience 25: 1904-1913.

[2] Eubanks et al. 2006. A molecular link between the active component of marijuana and Alzheimer's disease pathology. Molecular Pharmaceutics (E-pub ahead of print).

[3] Hampson et al. 1998. Cannabidiol and delta-9-tetrahydrocannabinol are neuroprotective antioxidants. Proceedings of the National Academy of Sciences 95: 8268-8273.

[4] Science News. June 11, 1998. “Marijuana chemical tapped to fight strokes.”

[5] Walther et al. 2006. Delta-9-tetrahydrocannabinol for nighttime agitation in severe dementia. Physcopharmacology 185: 524-528.

[6] BBC News. August 21, 2003. “Cannabis lifts Alzheimer’s appetite.”

[7] Volicer et al. 1997. Effects of dronabinol on anorexia and disturbed behavior in patients with Alzheimer’s disease. International Journal of Geriatric Psychiatry 12: 913-919.

source: NORML