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A new shows that 30 minutes of blue light therapy in the morning may improve sleep and reduce the severity of PTSD symptoms. Jane Khomi/Getty Images
  • Post-traumatic stress disorder (PTSD) may occur after a person experiences a traumatic event.
  • People with PTSD may experience flashbacks, anxiety, difficulty sleeping, and a variety of other symptoms.
  • Current treatments include psychotherapy, counseling, and medication.
  • A new study has found that just 30 minutes of blue light therapy in the morning may improve sleep and reduce the severity of PTSD symptoms.
  • The researchers suggest that this easy-to-use therapy could increase the efficacy of other PTSD treatments.

Most people will experience a shocking, scary or dangerous event at some time in their lives. This may lead to a range of reactions, from which many people may recover from.

But for some people, a traumatic experience will leave them with post-traumatic stress disorder (PTSD). In fact, around 6% of people in the United States will experience PTSD at some point in their lives.

PTSD may be treated with psychotherapy (talk therapy), counseling, and medications, such as antidepressants.

In a new study, researchers from the University of Arizona and Harvard Medical School found that exposure to blue light for just 30 minutes each morning may improve sleep quality and reduce symptom severity in people with PTSD.

William D. Killgore, Ph.D., principal investigator on the study, professor of psychiatry, psychology, and medical imaging, and director of the Social, Cognitive, and Affective Neuroscience (SCAN) Lab in the Department of Psychiatry at the University of Arizona College of Medicine, Tucson, told Medical News Today:

“We found that morning blue light exposure for half an hour each day was associated with improvement in total sleep time and some aspects of sleep quality in our sample of patients with PTSD. This improvement in sleep was also associated with in an increase in the volume of a brain structure called the amygdala (which is often reduced in size in people with PTSD).”

The study was recently published in Frontiers in Behavioral Neuroscience.

PTSD occurs when the usual short-term symptoms following a traumatic event persist for more than 1 month and start to impact daily life.

Symptoms of PTSD may include:

  • difficulty sleeping or disturbed sleep
  • flashbacks
  • bad dreams and frightening thoughts
  • avoidance of anything that might trigger memories of the event
  • being easily startled
  • angry outbursts
  • negative thoughts, depression, and anxiety.

Additionally, around 70-90% of people with PTSD report sleep disturbances, such as recurring nightmares and insomnia.

Prior studies have shown that sleep disruption adversely affects PTSD outcomes, so an improvement in sleep quality is often key to recovery.

At the start of the study, 82 participants, all of whom had clinically significant PTSD, completed two full-day neurocognitive assessments plus neuroimaging scans.

The researchers then randomly assigned participants into one of two groups. Both groups underwent 6 weeks of at-home light therapy, comprising 30 minutes of light exposure within 2 hours of waking and no later than 11 am. One group used a blue light device and the other used an amber light device.

The study was double-blind — neither participants nor the staff in direct contact with them knew whether they were having blue or amber light therapy.

“We selected blue because it is the wavelength of light that is most efficient for producing this shift in the biological clock,” Dr. Killgore explained.

“The retina of the eye has specific receptors that respond predominantly to the blue wavelengths of light (which is the primary wavelength of sunlight), and these receptors project to the circadian clock in the brain (a brain structure known as the suprachiasmatic nucleus of the hypothalamus). So, almost any light will work if it is bright enough, but blue tends to work most efficiently,” he added.

At the start of the study, the researchers assessed participants’ sleep quality, daytime sleepiness, and frequency and severity of nightmares.

After 6 weeks, all study participants reported an improvement in sleep quality, less disrupted sleep, and lower levels of insomnia and nightmares. But the blue-light group also saw a reduction in symptoms, something that was not seen in the control group.

By contrast, the amber-light group showed a return of their original fear memories.

“We found that the blue light treatment was effective at helping people to hold onto the benefits of a simple extinction treatment for fear memories. Specifically, the participants were conditioned to fear a particular picture by zapping them with a mildly annoying (but not painful) electric shock. Then we eliminated the fear response with a procedure called “extinction” (i.e., simply showing the picture over and over again without shock).”

– Dr. Killgore, Ph.D., principal investigator on the study

Dr. David A. Merrill, Ph.D., a geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center at Providence Saint John’s Health Center in Santa Monica, CA, not involved in the study, told MNT:

“Blue light exposure in the morning positively affects the brain to produce better sleep. Getting a good night’s sleep is critical to maximizing and maintaining the benefit seen with therapies for PTSD. Without the sleep, you’re more likely to lose the benefit.”

“It’s well known that morning light exposure, whether through sunlight or a high intensity light box, can help lessen symptoms of depression. Blue light has also been studied in TBI [traumatic brain injury] and shown to help cognitive recovery. This new study extends what we know about the benefits of light therapy to PTSD,” he added.

The authors propose that morning blue-light therapy might effectively complement other treatments for PTSD.

Despite the positive implications, however, it’s important to note the study was small in scale. More research is still needed before blue light therapy can be considered an effective treatment for PTSD.

“We didn’t conceive of the blue light treatment as a stand-alone therapy for PTSD, but as something to be used as an adjunctive treatment to improve sleep/daily rhythmicity [or] mood and facilitate the gains made in other therapies,” Dr. Killgore said.

“The light treatment could be used to sustain daily sleep and wake rhythms in a more healthy state. There are many available light devices that can be used for this purpose at a relatively modest cost.”

Dr. Merrill agreed and said the findings were “fascinating.”

“Morning blue light exposure looks like a promising add-on therapy for those undergoing treatment for PTSD using more conventional approaches like psychotherapy,” Dr. Merrill said.

The light therapy is low risk and well tolerated. It may also work as an anti-depressant, which is a 2-for-1 bonus.”