Despite what Halloween lore might have you believe, hypnosis isn't all about swinging watches, magic spells and mind control.
It is the oldest Western conception of psychotherapy and, in mainstream medicine, it has been shown to help patients manage pain, stress and anxiety and combat traumas and phobia. It is also associated with being used to retrieve "repressed" memories connected to mental disorders.
Now, new scientific research, bolstered by technological advances, is shedding light on the neurological nuances of the brain's response to hypnosis. For instance, a recent study from the Stanford University School of Medicine helps explain why some people easily fall into a trance while others do not.
David Spiegel, the study's senior author, defines hypnosis as a state of highly focused attention, achieved through deep breathing and muscle relaxation. When patients are fully hypnotized, they can, for instance, alter their minds to perceive pain as less painful.
"It's the equivalent in consciousness of a telephoto lens on a camera -- great detail, but not a lot of context," said Spiegel, medical director of Stanford's Center for Integrative Medicine.
The ability to slip into this mentality varies among people, according to Spiegel's study. Published in Archives of General Psychiatry, it shows that the reason may have to do with the strength of connections between specific brain regions.
Spiegel and his team performed brain-imaging scans on 12 adults considered highly hypnotizable and 12 others who were not so hypnotizable.
The researchers examined activity in different networks in their brains while they were relaxed and not hypnotized. They found that the highly hypnotizable patients showed greater activity between parts of the executive-control network, which is involved in making decisions, and the salience network, which is involved in deciding what is important.
"For the high hypnotizable, it was a high level of functional connectivity," Siegel said. "If executive control is on, so is the salient network. (They) tended to work together. That's the kind of absorption you see in highly hypnotizable people."
In contrast, the activity between those regions was very low in the less hypnotizable subjects.
Spiegel estimated that 10 percent of people are highly hypnotizable, one-third are not and the rest fall in between.
It is unclear why some people are more wired for hypnosis than others, but some theories posit that those who are hypnotizable especially enjoyed imaginative activities as children or learned early to focus their thoughts elsewhere in times of physical pain, Spiegel said. Another explanation holds that some people are genetically predisposed to produce certain neurotransmitters in a way that makes them more hypnotizable.
Katie Duchscherer, 21, a senior at Stanford, didn't know she was highly hypnotizable until Spiegel mass-hypnotized her class of 150. The psychology major has participated in his studies since then and learned how to slip into that focused state of mind on her own.
Duchscherer likens the feeling to intently reading a book to the point where the rest of the world seems to disappear.
"Hypnosis is actually similar to that, but instead of focusing on the TV you're watching or the book you're reading or the project you're working on, you're focusing on what's going on inside your head and what's going on inside your body," she said.
Self-hypnosis recently proved useful during a doctor's visit, when she had a wart on her foot frozen off with liquid nitrogen.
Was it painful? Sort of -- but Duchscherer said she was able to hypnotize herself into believing that she was running barefoot through the snow for fun. When it was over, her mother remarked that she hadn't even winced.