Similar polysomnographic pattern in primary insomnia and major depression with objective insomnia: a sign of common pathophysiology?

BACKGROUND Our aim is to verify empirically the existence of a major depressed subgroup with a similar polysomnographic pattern as primary insomnia, including at rapid eye movement sleep level. METHODS The polysomnographic data from 209 untreated individuals (30 normative, 84 primary insomnia sufferers, and 95 major depressed patients with objective insomnia) who were recruited retrospectively from the Erasme hospital database were studied for the whole night and thirds of the night. RESULTS Primary insomnia sufferers and major depressed patients with objective insomnia exhibit a similar polysomnographic pattern both for the whole night (excess of wake after sleep onset, deficit in slow-wave sleep/rapid eye movement sleep, and non-shortened rapid eye movement latency) and thirds of the night (excess of wake after sleep onset at first and last third, deficit in slow-wave sleep in first third, and deficit in rapid eye movement sleep in first and last third), including at rapid eye movement sleep level. CONCLUSION In our study, we demonstrated that major depressed patients with objective insomnia showed a similar polysomnographic pattern as primary insomnia, including at rapid eye movement sleep level, which supports the hypothesis of a common pathophysiology that could be hyperarousal. This opens new avenues for understanding the pathophysiology of major depression with objective insomnia.