Doctors at Harvard Medical School reviewed charts of older dementia patients from McLean Hospital in Belmont, Mass., and reported on 40 patients who experienced significant decreases in agitation after treatment with dronabinol, a man-made form of cannabis.

Although the pill also improved sleep, the doctors recorded 26 adverse events during the treatment period.

Other case reports suggest that some agitated dementia patients may improve with different forms of marijuana treatment.

However, some studies do point to potential side effects, including increased agitation and confusion.

In several states, including Arizona and Rhode Island, medical marijuana is approved for use in patients with Alzheimer’s disease and agitation.

Preliminary research published in the British Journal of Pharmacology suggests that some of the ingredients of marijuana may work to prevent Alzheimer’s and other forms of neurodegeneration.

The investigators found that marijuana cannabinoids minimize inflammation and protect neurons from oxidative stress, which has the potential to protect the brain from Alzheimer’s.

Yet experts caution that because of the potential negative effects of marijuana on the brain, further research is needed to prove that there is any brain-protective benefit from the drug.

Until results from placebo-controlled trials are available, marijuana is not recommended as a treatment for agitated dementia patients.