New 'unconscious' therapies may help treat phobias

If you’re terrified of spiders, a psychiatrist may suggest facing your fears by looking at photos or getting close to the real thing — not just once, but again and again. For someone with arachnophobia, this sounds like a worst nightmare.

Such ‘exposure therapy’ is a first-line treatment for phobias and other anxiety-related conditions. There is good evidence that it works:as the patient can be convinced to start And they manage to stick to it. When nothing bad happens repeatedly in feared situations, we eventually learn not to be afraid. However, there is no denying that it is distressing, and The failure rate can be as high as 45 percent. “People miss their exposure therapy appointments more often than they miss their dental appointments,” says psychologist Paul Siegel of Purchase College.

Or what if we could expose people to their fears without them being aware of it, allowing them to bypass the suffering and still reap the therapeutic benefits? It sounds strange, but a recent review of studies on different approaches to “unconscious exposure therapy” concluded that there is “sufficient evidence” that this approach is valid. These techniques could improve treatment compliance and may have broader implications for the treatment of conditions such as post-traumatic stress disorder (PTSD) and social anxiety.

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The review, conducted by Siegel and child psychiatrist Bradley Peterson of the University of Southern California, collected results from 39 studies covering 10 different techniques; 38 of them found positive effects. The researchers found that overall the approach is remarkably effective. “The unconscious exposure paradigm contradicts what is considered sacred dogma in cognitive behaviorism and clinical psychology,” says Siegel, “that is, if people want to overcome their fears, they must confront them.”

The first study on whether unconscious exposure to a fearful stimulus could reduce anxiety was published in 1978 and involved a film presented subliminally.

Researchers reduced the film’s exposure and placed a gray box over the projection area, making the film invisible. Participants with agoraphobia (the fear of being overwhelmed in public places) reported seeing ‘nothing’, but films depicting situations such as busy markets and public transport reduced their symptoms. However, the methods of this study had limitations, and subsequent research has used more rigorous approaches to assess participants’ awareness of unconsciously presented stimuli.

Siegel’s own work includes very short exposure (VBE), which uses a perceptual phenomenon called backward masking. Many images of feared stimuli such as spiders are presented for extremely short intervals (a few hundredths of a second), each immediately followed by a second, innocuous image, shown for much longer, and which has nothing to do with what triggered the fearful response. Because the image of the feared stimuli is shown very briefly and the longer-lasting image appears immediately afterwards, viewers are typically unaware of seeing the first image, but studies show that images presented in this way still engage unconscious brain processes seize.

Over the past fifteen years, Siegel and his colleagues have investigated VBE therapy with seven randomized, double-blind, placebo-controlled trials, the gold standard for clinical evidence. Most of these studies recruited participants with levels of arachnophobia that would qualify for a diagnosis and included a test involving approaching a spider. “We don’t joke around in my lab,” Siegel says. “We put them in a room with a live tarantula and see how much closer they can get to it.” He and his colleagues have repeatedly found that VBE significantly increases how close participants get to the tarantula and reduces the fear they report doing so. A follow-up study showed that these effects can last for a year.

Another technique, called ‘decoded neurofeedback’ or DecNef, involves persuading people to produce brain activity consistent with a fear, without showing them the fear-inducing stimulus itself. “We use (functional magnetic resonance imaging) to first figure out patterns of brain activity that represent the perception of some animals, such as spiders and snakes,” says Hakwan Lau, a psychologist now at the Institute for Basic Science in South Korea, who led the team that developed DecNef. “We then look for the occurrence of these patterns while people are still in the scanner.”

Participants are shown visual feedback that reflects their brain activity and are rewarded if they align it better with a target pattern. “We train people over the course of five sessions to activate that representation in their brains,” says Vincent Taschereau-Dumouchel, a neuroscientist now at the University of Montreal who led several DecNef studies. The process, he says, is intended to induce a kind of unconscious exposure. The researchers measured skin conductance (a physiological indicator of fear) and amygdala activity (the brain’s main emotion center) and found that DecNef reduces these biological fear markers for the target animal.

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

Some studies covered in the review examined what happens in the brain when feared stimuli are presented unconsciously, usually using VBE. These experiments have shown that unconscious presentation activates emotion regulation circuits and regions, including the amygdala, where unconscious fear memories are thought to be stored. The amygdala is activated during unconscious presentation, but the subsequent response to feared stimuli is reduced.

Research suggests that two brain circuits underlie fear: a conscious, cognitive system that stores explicit knowledge and beliefs about fears, and an unconscious system that activates automatic, physiological responses and works much faster. Unconscious exposure can change fear memories stored in the amygdala through the circuitry operating at the unconscious level. It is believed that these systems interact with each other, but how exactly is not clear.

In DecNef studies to date, the effects on biological responses did not change conscious fears. “Because the procedure is unconscious, it only changes the unconscious responses; it does not change the conscious fear itself,” says Lau. “But we hope that as methods improve, the effect will eventually be large enough to also influence conscious fear.”

In VBE studies there are participants did report lower subjective fear when approaching the spider, suggesting that reduced automatic, unconscious responses may allow conscious changes to occur more easily. This suggests that the most effective use of these unconscious techniques may be as an adjunct to traditional exposure therapies. “This can take the edge off,” says Siegel. “I’ve seen that it can reduce someone’s fears just enough that it makes it easier for them to put themselves in the spotlight, and I’d say clinically that’s really the goal.”

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