4. Decreased delta sleep ratio and elevated alpha power predict vulnerability to depression during interferon-alpha treatment

• Published in: Brain, behavior, and immunity behavior, and immunity, 2014-09, Vol.40, p.e2-e2
• Main Authors: Lotrich, F, Germain, A
• Format: Article
• Language: English
• Subjects: Allergy and Immunology; Psychiatry
• ISSN: 0889-1591; 1090-2139
• DOI: 10.1016/j.bbi.2014.06.024

Poor sleep often precedes depression. This is also true for depression occurring during interferon-a (IFN-a) therapy, where approximately one-quarter of non-depressed subjects develop depression by the second month. Those who sleep well remain relatively resilient. To implement potential depression prevention interventions, the specific sleep parameters that might influence depression resilience require determination. Therefore, two nights of polysomnography with quantitative EEG were obtained in 24 adult, euthymic subjects who subsequently were treated with IFN-a. Sleep parameters included the delta sleep ratio (DSR) (early-night restorative delta power) and alpha power (8–12 Hz; indexing hyperarousal). Every two weeks after starting IFN-a, a Beck Depression Inventory-II (BDI-II) score was obtained. The maximal increase in BDI-II from pre-treatment baseline – excluding the sleep question – was determined. As hypothesized, DSR was inversely associated with increases in BDI-II scores ( p < 0.01), as was increased alpha ( p < 0.01) and sigma power ( p < 0.01). In repeated-measure analyses of BDI-II over time, there was an interaction between alpha power and DSR ( p < 0.001). Subjects with low alpha power and normal DSR were resilient to developing depression. Most other sleep parameters were not associated with subsequent changes in depression. Both high DSR and low alpha/sigma power may be specific indices of resilience, but not other aspects of sleep. This suggests that sleep interventions to prevent depression may need to target these two sleep parameters.