Shining A Light On PTSD

It’s well known that spending time outdoors in the sunshine is good for your physical and mental well-being. But can light, such as bright therapeutic light or near-infrared light, be used to treat post-traumatic stress disorder (PTSD)? 

While admittedly limited and in its infancy, the research seems to suggest that these therapies could offer some form of relief for people living with PTSD. 

What is PTSD? 

PTSD is a psychological condition that can develop after experiencing a traumatic event such as a war, a physical attack, a near-fatal accident, physical or emotional abuse, or a natural disaster. However, not everyone who experiences a traumatic event necessarily goes on to develop PTSD. 

For example, approximately 12 million adults¹ in the United States will have PTSD during a given year, but a greater number will have experienced traumatic events. Prevalence figures suggest that roughly 6% of the US population will develop PTSD at some point in their lives, with women being twice as likely as men to develop the condition. 

It’s normal to experience some psychological upheaval after a traumatic event. But if the symptoms last longer than a month and start interfering with your daily functioning, you might have PTSD.

Symptoms of PTSD include:

• Upsetting thoughts, flashbacks, or nightmares about the event

• Avoidance of places, sensory input, or people who remind you of the trauma

• Numbing of general emotional responsiveness

• Increased irritability and hypervigilance

• Affected sleep.

What is bright light therapy?

Bright light therapy² works as a sunlight substitute. In countries with few hours of sunlight during wintertime, daily exposure to artificial bright light has been found to help with depression and seasonal affective disorder symptoms. 

The self-administered therapy involves sitting in front of bright light while going about your usual morning routine or wearing a device that looks like a large pair of goggles with light-emitting diode (LED) elements surrounding your eyes. 

Bright light therapy and PTSD

Researchers hypothesized that bright light therapy might be useful for treating PTSD because of a natural internal process called circadian rhythms regulating your sleep-wake cycle.

Evidence³ shows that people with intense symptoms of PTSD, including severe sleep disturbance, have an “evening chronotype”. This term means their circadian rhythm has been shifted to later in the day.

Bright light therapy can be used in an attempt to reset the clock; that is, to shift your circadian cycle back towards the morning. 

A small pilot study⁴ of people reporting symptoms typical of PTSD found that when the participants were exposed to an hour of bright light therapy early in the morning, some reduction in their PTSD symptoms occurred.  

A randomized controlled trial on the effect of bright light treatment on combat-related PTSD found that daily exposure to 30 minutes of bright light resulted in significant short-term improvements in the Clinician-Administered PTSD Scale in almost half of the participants. However, the treatment did not seem to have any antidepressant or anxiolytic effects. 

What is photobiomodulation?

Photobiomodulation⁵ is the use of red light or near-infrared light to heal or regenerate tissue that has been damaged or is in the process of degenerating. 

Numerous studies⁶ have proven the benefits of photobiomodulation. One study of note found that this treatment can have beneficial effects when applied to the brains of stroke patients. 

If the brain is the focus of the treatment, near-infrared light is often applied to the forehead because this allows for better penetration. The therapy often involves lasers, but recently, light-emitting helmets or ‘brain caps’ have been developed, which  use light-emitting diode (LED) arrays. 

Near-infrared light therapy and PTSD

While photobiomodulation is generally considered safe and without side effects, most studies related to photobiomodulation and PTSD have been animal studies. 

For example, a study⁷ examining brain activity in rats in response to traumatic events found that early photobiomodulation intervention modulated brain activity and prevented the occurrence of PTSD-like comorbidities in the rats. 

In theory, if such a study produced similar results in humans, photobiomodulation could be used in trauma survivors to reduce the possibility of developing PTSD. 

A small feasibility study that considered how using photobiomodulation on the brain in humans might benefit people with psychological disorders (three of the participants had PTSD) found that the treatment showed promise and that additional, more rigorous trials were necessary. 

What are eye movement desensitization and reprocessing therapy?

While eye movement desensitization and reprocessing⁸ (EMDR) therapy sounds like it should involve a brain cap or a pair of high-tech goggles, this treatment for PTSD doesn’t actually involve a light source at all.

Developed in 1987, this treatment is based on the theory that memories that haven’t been properly processed carry with them the emotions, thoughts, beliefs, and physical sensations of the trauma. 

When the memories are triggered, so are all these thoughts and feelings. EMDR therapy utilizes eye movements and other forms of rhythmic left-right stimulation (such as tapping) to change how memory is stored in the brain. EMDR therapy is typically carried out over a period of 6 to 12 sessions.  

The lowdown

While various psychotherapies and medications can be used to successfully treat PTSD, these treatments are not effective for everyone and, in the case of medications, are not without potential side effects. 

Light therapy, both bright light therapy, and near-infrared therapy show promise as treatments. However, far more extensive research is required to ascertain just how effective these therapies may be for people living with PTSD.