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Bernier, Denise,1953-
Sleep deprivation effects on mood and brain chemistry in unipolar depression.
Ph. D. -- Dalhousie University, 2008
Ottawa :Library and Archives Canada = Bibliothèque et Archives Canada,[2009]
4 microfiches
Includes bibliographical references.
'Background'. Partial or total overnight sleep deprivation has been shown to produce immediate antidepressive effects in about half of patients suffering from depression. This very rapid and robust response creates an opportunity to investigate the neurochemical changes associated with the improvement of depressive symptoms. 'Objectives'. Neurochemical correlates of responses to sleep deprivation were assessed in two brain regions of eleven young women with unipolar depression and of healthy controls, using localized proton magnetic resonance spectroscopy (1H-MRS) in a 1.5 tesla magnet. Neurochemical responses to sleep loss were expected to differ between depressed and control participants, and to correlate with the degree of mood improvement shown. 'Methods'. Participants were scanned on baseline day and at the same time of day 24 h later after having had the opportunity to sleep for only 2.5 h (22:30-01:00). Two spectroscopic volumes were selected: the left anterior dorsal prefrontal (LADPF) region and the pons. Three neurochemical signals were analysed, in reference to internal water (H2O): 'N'-acetylaspartate (NAA), Choline compounds (Cho), and total creatine-plus-phosphocreatine (tCr). Changes in the severity of depressive symptoms were monitored repeatedly using the Profile of Mood States (POMS) and a short version of the Hamilton Depression Inventory (HDI). 'Results'. About half the depressed participants showed at least 30% improvement in HDI mood (Responders), while the remainder showed no change or worsening in mood after sleep restriction (Non-responders). Baseline pontine Cho:H2O values were abnormally low in subsequent Non-responders but not in subsequent Responders to sleep loss. After sleep restriction, a significant 17.9% increase in mean Cho:H2O was observed in the LADPF region of the Depressed group, and a 20.1% decrease in pontine tCr:H 2O of Depressed and Control groups combined. At baseline, greater sadness (HDI) in depressed participants was associated with lower prefrontal NAA:H 2O. After sleep restriction, an improvement in Fatigue (POMS) in depressed participants was correlated with the degree of reduction in pontine Cho:H 2O. 'Conclusions'. Phospholipid metabolism appears to be implicated in the antidepressant effects of sleep deprivation in both pontine and LADPF regions. Changes in creatine metabolism in the pons after sleep restriction may be found in both healthy and depressed people.