Mood regulation in seasonal affective disorder patients and healthy controls studied in forced desynchrony

Abstract

Mood regulation in seasonal affective disorder patients and healthy controls studied in forced desynchrony Koorengevel, Kathelijne M.; Beersma, Domien G.M.; den Boer, Johan A. ; Hoofdakker, Rutger H. van den Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractIn healthy subjects, both the duration of wakefulness and the circadian pacemaker have been demonstrated to be involved in the regulation of mood. Some features of affective disorders suggest that these two factors also play a role in the dysregulation of mood. In particular, disturbances of the circadian pacemaker have been proposed to be a pathogenetic factor in Seasonal Affective Disorder, winter type (SAD). This report presents a test of this proposition. To this end seven SAD patients and matched controls were subjected to a 120-h forced desynchrony protocol, in which they were exposed to six 20-h days. This protocol enables us to discriminate the extent to which the course of mood is determined by the imposed 20-h sleep-wake cycle from the influence of the circadian pacemaker on that course. Patients participated during a depressive episode, after recovery upon light therapy and in summer. Controls were studied in winter and in summer. Between SAD patients and controls no significant differences were observed in the period length nor in the timing of the endogenous circadian temperature minimum. In both groups, sleep-wake cycle-and pacemaker-related components were observed in the variations of mood, which were not significantly different between conditions. ᮊ

Can light make us bright? Effects of light on cognition and sleep

“…The desynchronized/ synchronized subjects Au4 sleep at different circadian phases of the entire 24-h cycle, which enables to differentiate the contribution of the sleep homeostatic process or the circadian system to a given variable (Dijk et al, 1997). Usually-but not always-both factors contribute substantially to measures as alertness, mood, and neurob Au5 ehavioral performance (Cajochen et al, 1999a, b;Koorengevel et al, 2003). Accordingly, some forced desynchrony studies have revealed that the deleterious effects of prior wakefulness on alertness were strongest during the minimum of the endogenous CBT rhythm.…”

Biological rhythm disturbances in mood disorders

“…However, most variables show varying degrees of interaction. Both factors contribute substantively to such subjective measures as mood (Koorengevel et al, 2003) or performance (Cajochen et al, 1999). These are the protocols required for a new generation of studies of circadian disorders in depression (Wirz-Justice, 2003).…”

Chronobiology, excessive daytime sleepiness and depression: Is there a link?

“…The desynchronized subjects sleep at different circadian phases of the entire 24-h cycle, and subsequent analyses can differentiate the relative contribution of the sleep homeostat or the biological clock to a given variable [66]. Usually -but not always -both factors contribute substantially to subjective measures, such as mood, sleepiness and neurobehavioral performance [67,68]. However, only few studies have used these techniques in a controlled manner to unmask the contribution of the circadian clock in depression.…”

“…These protocols can certainly contribute to a more accurate understanding of the circadian disruptions that occur in depression, and, thus, can be of substantial value in future research [9]. Table 1 gives an overview of constant routine and forced desynchrony studies in depressed patients [69][70][71][72]67,73].…”