Hyperstable regulation of vigilance in patients with major depressive disorder

Abstract

Objectives. This study tested the hypothesis that patients with depression show less and later declines into lower EEG vigilance stages (different global functional brain states) under resting conditions than healthy controls, as proposed by the vigilance theory of affective disorders. Methods. Thirty patients with Major Depressive Disorder (19 female; mean age: 37.2 years, SD: 12.6) without psychotropic medication and 30 carefully age- and sex-matched controls (19 female; mean age: 37.3 years, SD: 12.8) without past or present mental disorders underwent a 15-min resting EEG. EEG-vigilance regulation was determined with a computer-based vigilance classification algorithm (VIGALL, Vigilance Algorithm Leipzig), allowing a classification of vigilance stages A (with substages A1, A2 and A3), B (with substages B1 and B2/3) and C. Results. Depressive patients spent significantly more time in the highest EEG vigilance substage A1, and less time in substages A2, A3 and B2/3 than controls. In depressive patients, a significantly longer latency until the occurrence of substages A2, A3 and B2/3 was observed. No significant group differences in the percentage of B1 segments or the latency until occurrence of B1 were found. Conclusions. The results confirm the hypothesis that patients with depression show less (and later) declines into lower EEG vigilance stages under resting conditions than healthy controls, and support the vigilance theory of affective disorders linking a hyperstable vigilance regulation to depression.

Key words::

• Affective disorders
• major depressive disorder
• EEG
• vigilance
• VIGALL

Acknowledgements

The authors wish to thank Ines Thomas, Mandy Siebert and Frauke Möller for conducting the resting EEGs, Michael Adamazsek and Jens Dietzel for assistance in their clinical evaluation and Roland Mergl for critical discussion of statistical questions.

Statement of Interest

Ulrich Hegerl has been and is participating in advisory boards of Lilly, Wyeth, Lundbeck and Sanofi-Aventis. He received honoraria for single lectures as well as sponsoring for symposia and an internet service from Cephalon and other pharmaceutical companies, health insurances and parties. Peter Schoenknecht has received sponsorship and honoraria for lectures from Lilly, Astra-Zeneca, Novartis, Pfizer, Janssen-Cilag, and Merz.

Kathrin Wilk, Sebastian Olbrich and Christian Sander declare no potential conflicts of interest.