New “unconscious” therapies may help treat phobias

If you are afraid of spiders, a psychiatrist may suggest that you face your fears by looking at pictures or getting up close to the real thing—not just once, but over and over again. For someone with arachnophobia, this sounds like the worst nightmare.

Such “exposure therapy” is the first method of treating phobias and other conditions related to fear. There is strong evidence that it works—if the patient can be persuaded to start and they manage to stick to it. When nothing bad happens all the time in scary situations, we eventually learn not to be afraid. There’s no denying that it’s frustrating, and the dropout rate can be as high as 45 percent. “People miss exposure therapy appointments more often than they miss the dentist,” says psychologist Paul Siegel of Purchase College.

Alternatively, what if we could expose people to their fears without them realizing it, allowing them to bypass the trouble while reaping the therapeutic benefits? It sounds strange, but ah last review studies of different approaches to “unconscious influence therapy” concluded that there is “sufficient evidence” that the approach is valid. These techniques may improve compliance with exposure therapy and may have broader implications for the treatment of conditions such as post-traumatic stress disorder (PTSD) and social anxiety disorder.

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The review, conducted by Siegel and child psychiatrist Bradley Peterson of the University of Southern California, compiled the results of 39 studies that covered 10 different techniques; 38 of them showed a positive effect. The researchers found this approach to be extremely effective overall. “The paradigm of unconscious influence runs counter to what is considered the sacred dogma of cognitive behaviorism and clinical psychology,” says Siegel, “that if people want to overcome their fears, they must face them.”

In 1978, the first study was published that investigated whether unconscious exposure to a fearful stimulus could reduce anxiety and involved a film that was shown subliminally.

The researchers reduced the brightness of the film and placed a gray frame over the projection area, covering the film. Participants with agoraphobia (fear of being startled in public places) reported that they “couldn’t see anything”, but films depicting situations such as crowded markets and public transport reduced their symptoms. However, the methods of this study had limitations, and subsequent studies used more rigorous approaches to assess participants’ awareness of unconsciously presented stimuli.

Siegel’s own work involves “very short exposure,” or VBE, which uses a perceptual phenomenon called reverse masking. Many images of fear-inducing stimuli, such as spiders, are presented for very short intervals (a few hundredths of a second), each immediately followed by a second, harmless image shown for much longer that has nothing to do with the fear response. Because images of fear-inducing stimuli are shown very briefly and the long-lasting image appears immediately afterward, viewers are usually unaware that they are seeing the first image, but research shows that images presented in this way still engage unconscious brain processes.

Over the past 15 years, Siegel and colleagues have investigated VBE therapy in seven randomized, double-blind, placebo-controlled trials, the gold standard of clinical evidence. Most of these studies recruited participants with a level of arachnophobia that would qualify for diagnosis and included a spider approach test. “We don’t joke around in my lab,” Siegel says. “We put them in a room with a live tarantula and see how close they can get to it.” He and his colleagues repeatedly found that VBE significantly increased participants’ approach to the tarantula and reduced the fear they reported doing so. One follow-up assessment found that these effects may persist for a year.

Another technique, called “decoded neurofeedback,” or DecNef, involves getting people to produce brain activity corresponding to fear without showing them the fear-inducing stimulus itself. “We are using (functional magnetic resonance imaging) to first elucidate patterns of brain activity that represent perception in some animals, such as spiders and snakes,” said Hakwan Lau, a psychologist at the Institute of Basic Science in South Korea who led the team , which developed DecNef. “Then we look for instances of these patterns appearing while people are still inside the scanner.”

Participants are shown visual feedback representing their brain activity and rewarded for matching the target pattern more closely. “We train people to activate this representation in their brain over five sessions,” says Vincent Tachereau-Dumouchel, a neuroscientist at the University of Montreal who has led several DecNef studies. The process, he says, is designed to create a type of unconscious influence. The researchers measured skin conductance (a physiological indicator of fear) and activity in the amygdala (the brain’s main emotion center) and found that DecNef reduced these biological markers of fear in the target animal.

Other approaches include bypassing conscious awareness by presenting stimuli that have been associated with fear, such as smells or sounds, during sleep. Another, called “spider-free arachnophobia therapy,” involves showing images of objects that have arachnoid features, such as a tripod with spider-like legs.

Some of the studies reviewed in the review investigated what happens in the brain when fear-inducing stimuli are presented subliminally, mostly through VBE. These experiments found that subliminal representation activates emotion regulation circuits and regions, including the amygdala, where unconscious fear memories are thought to be stored. The amygdala is activated during subliminal presentation, but its subsequent response to fearful stimuli is reduced.

According to research, two brain circuits underlie fear: a conscious cognitive system that stores clear knowledge and beliefs about fears, and an unconscious system that activates automatic physiological responses and works much faster. Unconscious exposure can alter fear memories stored in the amygdala through circuitry that operates at an unconscious level. These systems are believed to interact, but exactly how is unclear.

In studies of DecNef so far, effects on biological responses have not changed conscious fears. “Because the procedure is unconscious, it only changes unconscious reactions; it doesn’t change the conscious fear itself,” says Lau. “But we hope that as the methods improve, the effect will be large enough to affect conscious fear as well.”

However, in VBE studies, participants did report less subjective fear when approaching a spider, suggesting that a reduction in automatic unconscious responses may facilitate greater readiness for conscious change. This suggests that the most effective use of these unconscious techniques may be as an adjunct to traditional exposure therapy. “It can reduce the aggravation,” Siegel says. “I could see that it could reduce someone’s fears enough to make it easier for them to participate in exposure, and I would say clinically, that’s really the goal.”

These findings may have broader implications than just the fear of spiders. “As far as we know, the underlying mechanisms of fear are at work whether you’re afraid of heights, public speaking, blood, traumatic memories, or interacting with strangers,” says Siegel. “We are in the middle of studies applying VBE to social anxiety disorder in young adults and combat veterans injured in Iraq and Afghanistan.”