Extremely low levels of THC compound, a chemical found in marijuana, may slow down or halt the progression of Alzheimer's disease, US neuroscientists have found, thus laying the ground for the development of effective treatment in the future.

In recent research published in the Journal of Alzheimer's Disease, scientists from University of South Florida revealed their findings, that may shed light on controversial therapeutic qualities of marijuana.

Alzheimer’s disease is one of the most common dementia types in people over 65. It develops alongside malfunctioning or death of nerve cells in the brain, which usually results in changes in one’s memory, behavior, and ability to think clearly. Its history dates back to over a century, but its origins remain largely unknown. Alzheimer’s disease tends to progress from mild forms to moderate and severe cases at different rates, eventually leading to death.

As the team found, extremely low doses of delta-9-tetrahydrocannabinol chemical, also known as THC, reduce the production of amyloid beta protein, as well as prevent it from accumulating in abnormal amounts. What is special about this protein is that it is found in a soluble form in most aging brains. It also marks early evidence for Alzheimer's disease.

A “natural and relatively safe amyloid inhibitor”, THC can fight Alzheimer’s, slowing down its development or even curing it. According to the scientists, its low concentrations also play a positive part in mitochondrial function, thus adding up to the processes of energy supply, signal transmission and maintenance of a healthy brain.

"THC is known to be a potent antioxidant with neuroprotective properties, but this is the first report that the compound directly affects Alzheimer's pathology by decreasing amyloid beta levels, inhibiting its aggregation, and enhancing mitochondrial function,"said study lead author Chuanhai Cao, PhD and a neuroscientist at the Byrd Alzheimer's Institute and the USF College of Pharmacy.

However, even the researchers “are still far from a consensus”, as Neel Nabar, a study co-author and MD/PhD candidate mentioned. The reason for this controversy is the subtlety of the following fact: the positive impact of low doses of THC doesn’t rule out its toxicity and memory impairment.

Another issue concerning cannabis use that has to be solved by drug developers is legal restrictions. For instance, in the US Marijuana is regarded as a medical drug only in a number of states – Colorado and Washington, D.C. This is also true for some countries like the Netherlands and Uruguay.

“It's important to keep in mind that just because a drug may be effective doesn't mean it can be safely used by anyone. However, these findings may lead to the development of related compounds that are safe, legal, and useful in the treatment of Alzheimer's disease", Nabar outlined.

Nowadays, medical marijuana is mainly used as a pain killer. It deals with headaches, pains from cancer, or in cases when a patient has a long-term condition, such as glaucoma, HIV or nerve pain. Still, its side effects include dizziness and euphoria, but in more serious cases it could be severe anxiety and psychosis.