Abstract
Background: Partial or total overnight sleep deprivation produces immediate mood improvement in about 50% of patients with depression, but not in healthy controls. Our objectives were to compare the neurochemical changes that accompanied partial overnight sleep deprivation in healthy and depressed participants, and to compare baseline neurochemical profiles and overnight neurochemical changes between those depressed participants who did and did not respond to sleep loss with mood improvement. Methods: We studied 2 brain regions (left dorsal prefrontal area and pons) in 12 women with unipolar depression and in 15 healthy women using proton magnetic resonance spectroscopy acquired at 1.5 T. The scans took place at baseline and 24 hours later after a night with sleep restricted to a maximum of 2.5 hours (22:30-01:00). We assessed 3 neurochemical signals (referenced to internal water): N-acetylaspartate (NAA), choline compounds (Cho) and creatine-plus-phosphocreatine (tCr). Results: In both groups combined, sleep restriction caused a 20.1% decrease in pontine tCr (F1-16 = 5.07, p = 0.039, Cohen's d = 0.54) and an 11.3% increase in prefrontal Cho (F1-21 = 5.24, p = 0.033, Cohen's d = 0.46). Follow-up tests revealed that prefrontal Cho increases were significant only among depressed participants (17.9% increase, t9 = -3.35, p = 0.008, Cohen's d = 1.06). Five depressed patients showed at least 30% improvement in mood, whereas 6 showed no change or worsening in mood after sleep restriction. Baseline pontine Cho levels distinguished subsequent responders from nonresponders to sleep restriction among depressed participants (z = 2.61, p = 0.008). Limitations: A limitation of this study is the relatively small sample size. Conclusion: Sleep restriction altered levels of pontine tCr and prefrontal Cho in both groups combined, suggesting effects on phospholipid and creatine metabolism. Baseline levels of pontine Cho were linked to subsequent mood responses to sleep loss, suggesting a role for pontine phospholipid metabolism in mood effects of sleep restriction.
| Original language | English |
|---|---|
| Pages (from-to) | 352-360 |
| Number of pages | 9 |
| Journal | Journal of Psychiatry and Neuroscience |
| Volume | 34 |
| Issue number | 5 |
| Publication status | Published - Sept 2009 |
Bibliographical note
Funding Information:Acknowledgments: This research was supported by grants from the Nova Scotia Capital District Health Authority Research Fund and the Department of Psychiatry, Dalhousie University. It was submitted in partial fulfillment of the requirements for a PhD degree (D.B.) at Dalhousie University. We thank Carl Helmick, Mark Given, Matthew Rogers and Gregory McLean for their invaluable technical assistance; the late Vivek Kusumakar for his support and encouragement; Sonia Chehil and Marina Sokolenko for clinical support; Mohamed Abdolell and Wade Blanchard for their useful advice on statistical analyses; and three anonymous reviewers for numerous helpful suggestions.
ASJC Scopus Subject Areas
- Psychiatry and Mental health
- Biological Psychiatry
- Pharmacology (medical)
