New Study Shows Sleep can Reduce Fear

A fascinating new study published in the journal Nature Neuroscience reveals that for those who have phobias and fears, the solution to their problem may come in their sleep. The study was conducted by Katherina Hauner, the assistant director of the Cognitive Neuroscience Laboratory of the Rehabilitation Institute of Chicago at the Northwestern University Feinberg School of Medicine, and its results indicated that people’s fears could be reduced simply by sending a sensory cue linked to the phobia while they were sleeping.  The study used mild shock to invoke a fear response – shock is one of the most commonly-used forms of fear conditioning in psychological studies. Fifteen study participants were exposed to two different faces at the same time that they received the mild shock; at the same time they were exposed to the specific strong and memorable scents of mint and lemon. Each scent was associated with a different one of the faces. The reason for using scent as part of the experiment is that our bodies detect and recognize smells even when we are asleep. Once the experiment’s researchers determined that the fear response was firmly conditioned in the study participants and that they had learned to fear the faces as well as the smells that were accompanied by the shocks, they asked the participants to take a nap while hooked up to sleep study technology to monitor their brain wave movement. Once each participant had entered into the phase of sleep known as slow wave, the researchers again exposed them to one of the smells that they had been taught to fear. Though the smells evoked a strong fear response when they were first detected during sleep, the longer the participant was in the slow wave state and exposed to the smell, the more the fear response dissipated. Perhaps most interestingly, following their naps, the participants were again exposed to the pictures of the faces that they had been conditioned to fear, and when they saw the face that had been associated with the smell that they were exposed to while they slept, their fear response while awake was markedly reduced. This means that the change that took place during their slow phase sleep cycle was actually learned. Adjustments to the amount of time that each subject was exposed to the smell while they were asleep made direct correlative differences in the amount of fear that was experienced when they were awake. The study’s results are of great interest to those in the world of psychiatry. According to Edward Pace-Schott, an assistant professor of psychiatry at the Harvard Medial School, “it suggests that if you can get contextual information into the brain during sleep, some sort of learning process can take place. The fact that it gets into the brain during sleep is remarkable.” The possibility exists that this discovery can be used to assist people who suffer from acute phobias, post-traumatic stress disorder, and other psychological issues that impact the quality of their lives.