A Nonpharmacologic Method for Enhancing Sleep in PTSD
[Technical Report, Final Report]
University of Arizona
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Sleep disturbance is nearly ubiquitous among individuals suffering from PTSD and is a major problem among service members returning from combat deployments. Recent evidence suggests that adequate restorative sleep may a crucial component in the ability to generalize fear extinction learning, and ultimately may be a key feature in the process of recovery from PTSD. Based on accumulating evidence that the circadian system and sleep-wake patterns are quite powerfully affected by exposure to light, we proposed to use light therapy to regulate the sleep wake schedule of individuals with PTSD, thereby potentially enhancing recovery. Further, because blue-wavelengths have been shown to activate specific intrinsically photosensitive retinal ganglion cells ipRGCs, that play a key role in regulating the circadian pacemaker in the suprachiasmatic nucleus of the hypothalamus, we hypothesized that blue light therapy BLT would be more effective than a similar amber wavelength light therapy ALT. We compared 6-weeks of BLT versus ALT on a variety of sleep, symptom, cognitive, and brain outcome measures in individuals meeting criteria for PTSD. Overall, we found that BLT was more effective than ALT at improving total sleep time. These improvements in the amount of sleep were associated with reductions in PTSD symptoms on the CAPS. Additionally, the BLT condition was associated with greater retention of extinction memories following a fear conditioning and extinction protocol. Moreover, the BLT condition was associated with an increase in ventral-medial prefrontal activation and a decrease in dorsolateral prefrontal and amygdala activation in response to previously feared and then extinguished stimuli. We also demonstrated that decreased activation was observed across many of the anatomical regions associated with fear-based responses, including the hippocampus, insula, and dorsal anterior cingulate cortex for BLT versus ALT.
- Stress Physiology
- Stress Physiology