Blunted Nocturnal Salivary Melatonin Secretion Profiles in Military-Related Posttraumatic Stress Disorder

Michel A Paul; Ryan J Love; Rakesh Jetly; J Donald Richardson; Ruth A Lanius; James C Miller; Michael MacDonald; Shawn G Rhind

doi:10.3389/fpsyt.2019.00882

Blunted Nocturnal Salivary Melatonin Secretion Profiles in Military-Related Posttraumatic Stress Disorder

Front Psychiatry. 2019 Dec 6:10:882. doi: 10.3389/fpsyt.2019.00882. eCollection 2019.

Authors

Michel A Paul¹, Ryan J Love¹, Rakesh Jetly², J Donald Richardson^{3

4

5

6}, Ruth A Lanius^{3

7}, James C Miller⁸, Michael MacDonald², Shawn G Rhind¹

Affiliations

¹ Defence Research & Development Canada, Toronto Research Centre, Operational Health and Performance Section, Toronto, ON, Canada.
² Directorate of Mental Health, Canadian Forces Health Services, Ottawa, ON, Canada.
³ Department of Psychiatry, Western University, London, ON, Canada.
⁴ Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
⁵ Operational Stress Injury Clinic, Parkwood Institute, London, ON, Canada.
⁶ MacDonald Franklin Operational Stress Injury Research Centre, Lawson Research Institute, London, ON, Canada.
⁷ Department of Neuroscience, Western University, London, ON, Canada.
⁸ Department of Life Sciences, Texas A&M University Corpus Christi, Corpus Christi, TX, United States.

Abstract

Background: Sleep disturbances are a hallmark of posttraumatic stress disorder (PTSD), yet few studies have evaluated the role of dysregulated endogenous melatonin secretion in this condition. Methods: This study compared the sleep quality and nocturnal salivary melatonin profiles of Canadian Armed Forces (CAF) personnel diagnosed with PTSD, using the Clinician Administered PTSD Scale (CAPS score ≥50), with two healthy CAF control groups; comprising, a "light control" (LC) group with standardized evening light exposure and "normal control" (NC) group without light restriction. Participants were monitored for 1-week using wrist actigraphy to assess sleep quality, and 24-h salivary melatonin levels were measured (every 2h) by immunoassay on the penultimate day in a dim-light (< 5 lux) laboratory environment. Results: A repeated measures design showed that mean nocturnal melatonin concentrations for LC were higher than both NC (p = .03) and PTSD (p = .003) with no difference between PTSD and NC. Relative to PTSD, NC had significantly higher melatonin levels over a 4-h period (01 to 05 h), whereas the LC group had higher melatonin levels over an 8-h period (23 to 07 h). Actigraphic sleep quality parameters were not different between healthy controls and PTSD patients, likely due to the use of prescription sleep medications in the PTSD group. Conclusions: These results indicate that PTSD is associated with blunted nocturnal melatonin secretion, which is consistent with previous findings showing lower melatonin after exposure to trauma and suggestive of severe chronodisruption. Future studies targeting the melatonergic system for therapeutic intervention may be beneficial for treatment-resistant PTSD.

Keywords: circadian; dim light melatonin onset; melatonin; post-traumatic stress disorder; saliva; sleep disturbance.