Originally appeared at http://www.aolhealth.com/2011/01/04/salvia-pain-alzheimers-disease/. Doctors hope further studies of salvia, a powerful hallucinogen that is sometimes smoked by recreational users, will unlock treatments for a variety of neurological disorders including Alzheimer’s disease and illnesses that cause chronic pain. Researchers at Johns Hopkins Hospital recently completed a study that examined the effects of salvia or salvinorin A, on humans. “It is unlike anything that exists,” Dr. Matthew Johnson, lead study researcher, psychologist and assistant professor of psychiatry at John Hopkins University, told AOL Health. Johnson believes that gaining information about how salvia affects the brain could lead to medical advances and the creation of new drugs to treat a variety of illnesses and conditions that affect the brain. Salvia divinorum is the active ingredient in salvia, which resembles marijuana and, according to researchers, is the most powerful hallucinogen in nature. This study, which appears online in Drug and Alcohol Dependence, is the first controlled trial to be conducted on humans. The study participants were two men and two women who had previous experience with hallucinogens. The volunteers smoked the drug in 20 sessions over the course of two or three months. They inhaled a range of doses of the drug in pure form and were asked to rate its strength. Due to the extreme effects of this often controversial drug, participants were allowed to take breaks when needed and were told they could completely withdraw from the study at any time. Participants reported they had an awareness of where they were after smoking the drug, but they also had a feeling of “leaving this reality completely and going to other worlds or dimensions and interacting with entities,” Johnson told ABC News. The participants also showed no changes in heart rate or blood pressure, and the study concluded that the drug has no physically adverse effects on otherwise healthy people. According to an animal study, salvinorin A activates opioid receptors in the brain. When salvinorin A acts on these receptors, a person feels high. Addictive drugs, such as morphine, also stimulate opioid receptors. However, salvinorin A stimulates another type of receptor called the kappa opioid. “It is unique in the way it affects the kappa system,” explains Johnson. “Salvinorin A selectively hits the kappa receptors and affects them more cleanly than any other drugs.” Because of their structure, salvia molecules have smaller impact on the brain’s processes, and have less potential for addiction. Johnson says there are many possibilities for the use of this drug. “Right now, we’re just understanding its basic effects on humans,” says Johnson. Future studies and research will provide more information on the possibilities for this new drug. Salvia is legal to buy and sell in many U.S. states; however, the U.S. Department of Justice’s Drug Enforcement Administration has labeled salvia a drug of concern. To date, 13 states have adopted legislation that bans or regulates the use of salvia. In addition, legislators and federal officials in many other states are considering regulating the drug. Researchers at Johns Hopkins Hospital led by Dr. Matthew Johnson recently completed a study of the physiological and subjective effects of smoked Salvia divinorum in humans. While studies have previously explored the effects of salvia on animals, this was the first controlled trial of the drug on humans. Researchers hope that additional studies will uncover possible medical and therapeutic uses for salvia, but acknowledge that much work remains to be done.