The U.S. Drug Enforcement Agency (DEA) considers marijuana a Schedule I narcotic, and as such is considered to have no medical value. Medical research is continuing to show otherwise.

The Salk Institute located in La Jolla, California, recently reported that a team of scientists have demonstrated that the psychoactive ingredient in marijuana — tetrahydrocannabinol, or THC — may help remove the "cellular glue" that is part of the damaging pathology in Alzheimer's disease. The results have been published in the June issue of Nature.

A classic finding in those with Alzheimer's disease is clumping of the sticky substance amyloid beta, a protein that is toxic and harmful to brain function. Earlier research had shown how THC contributed to the reduction in the sticking together of amyloid proteins in animal models.

The work undertaken at the Salk Institute was on human neurons grown in the laboratory and provides insight into the process of Alzheimer's disease. The neuron model showed that amyloid beta initiates an inflammatory response that contributes to cell death. THC stimulate the removal of the toxic amyloid beta, helped block inflammation and was protective of neurons.

"Although other studies have offered evidence that cannabinoids might be neuroprotective against the symptoms of Alzheimer's, we believe our study is the first to demonstrate that cannabinoids affect both inflammation and amyloid beta accumulation in nerve cells," Professor David Shubert, the senior author on the publication, stated.

Reaction to viral load and inflammatory responses are considered to be contributing factors to Alzheimer's disease.

"Inflammation within the brain is a major component of the damage associated with Alzheimer's disease, but it has always been assumed that this response was coming from immune-like cells in the brain, not the nerve cells themselves," said Antonio Currais, lead author of the paper. "When we were able to identify the molecular basis of the inflammatory response to amyloid beta, it became clear that THC-like compounds that the nerve cells make themselves may be involved in protecting the cells from dying."

The Salk Institute study adds to a growing body of research supporting the use of cannabinoids for the treatment of Alzheimer's disease. There are studies demonstrating a decrease in the behavioral symptoms of AD as well as improvement in sleep quality with the proper use of cannabis/marijuana. Schubert emphasized that his team's findings were conducted in exploratory laboratory models, and that the use of THC like compounds as a therapy would need to be tested in clinical trials. Further studies are certainly warranted.

However, there are barriers to such work as marijuana is classified as a Schedule I drug: "Schedule I drugs, substances, or chemicals are defined as drugs with no currently accepted medical use and a high potential for abuse. Schedule I drugs are the most dangerous drugs of all the drug schedules with potentially severe psychological or physical dependence."

Alzheimer's disease affects more than 5 million people in the United States. A treatment that removes the sticky aggregates of amyloid beta and reduces the inflammation certainly is of value.