The December, 2007, issue of Scientific American Mind contains an excellent article by David Jay Brown on the resurgence of psychedelic drug research over the past fifteen years. A growing number of studies using human volunteers have begun to explore the possible therapeutic benefits of drugs such as LSD, psilocybin, DMT, MDMA, ibogaine, and ketamine. Here is the lead:

Much remains unclear about the precise neural mechanisms governing how these drugs produce their mind-bending results, but they often produce somewhat similar psychoactive effects that make them potential therapeutic tools. Though still in their preliminary stages, studies in humans suggest that the day when people can schedule a psychedelic session with their therapist to overcome a serious psychiatric problem may not be that far off.

Current studies are focusing on psychedelic treatments for cluster headaches, depression, obsessive-compulsive disorder (OCD), severe anxiety in terminal cancer patients, post-traumatic stress disorder (PTSD), alcoholism and opiate addiction.

Neuropharmacologist David E. Nichols of Purdue University says that there are at least two possible mechanisms for beneficial actions. “The first simply involves a change in the numbers of brain serotonin 2A receptors. Activation of serotonin 2A receptors by psychedelics causes the number of receptors expressed on the surface of neurons to decrease, a process called downregulation. For some disorders, such as OCD, it may be this receptor downregulation that could be therapeutic.”

“The other possible mechanism,” he continues, “is a psychological effect that is harder to define but in some way produces changes in the way the subject perceives pain and distress. Psychedelics seem able to produce a profound cognitive change that provides the patient with a new insight — the ability to see the world from a new perspective — somehow reducing anxiety and raising the pain threshold.”

The article concludes:

Although we are still in the early days of psychedelic therapy research, the initial data show considerable promise. A growing number of scientists believe that psychedelic drugs may offer safe and effective help for people with certain treatment-resistant psychiatric disorders and could possibly help some people who receive partial relief from current methods to obtain a more complete healing.