Circadian preference and sleep quality in healthy controls and psychiatric inpatients with major depressive disorder - An actigraphy study incorporating morning and evening mood assessments.

Major depressive disorder (MDD) is frequently accompanied by sleep disturbance. Regarding diurnal preference (chronotype), sleep problems and low mood have been associated with evening orientation. Considering diurnal preference, we investigated subjective restorative value of sleep and actigraphy sleep parameters together with mood assessments twice a day, i.e. in the morning and evening, during weekdays and weekends in MDD psychiatric inpatients and healthy controls (HCs). The restorative value of sleep was higher during the weekend in HC, and bedtimes and risetimes were delayed during the weekend compared to weekdays in HC and MDD. Morning mood affected subjective sleep ratings in both groups, while association with symptom severity (BDI) in MDD remained insignificant. In HC, better evening mood was associated with later bedtimes. Regarding the chronotype in HC, evening orientation was associated with relatively low restorative value of sleep during weekdays, and morning orientation was associated with relatively higher actigraphy sleep efficiency during weekdays compared to weekend. In MDD, an association of evening orientation with later rise times could be observed, while no chronotype dependent effect emerged regarding the restorative value of sleep or sleep efficiency. Our results emphasize that research on sleep in MDD should incorporate weekdays as well as weekends, chronotype assessment, and measures of morning and evening mood, as these can be associated with ratings of the subjective restorative value of sleep (i.e. in our study, better morning mood was associated with higher restorative values), but also with behavioral sleep parameters (i.e. in our study, more positive evening mood was associated with later bedtimes). Potentially, the restorative value of sleep in MDD evening types can be improved by maintaining a regular sleep schedule, which needs to be investigated in an experimental design.

Influence of chronotype on daily mood fluctuations: pilot study in patients with depression.

Depression risk is associated with a late chronotype pattern often described as an 'evening chronotype'. Fluctuations in mood over consecutive days have not yet been measured according to chronotype in in-patients with depression. A total of 30 in-patients with depression and 32 healthy controls matched for gender and age completed a chronotype questionnaire and twice-daily ratings on mood for 10 consecutive days (registered in the German Clinical Trials Register: DRKS00010215). The in-patients had Saturdays and Sundays as hospital-leave days. The relationship between chronotype and daily mood was mediated by the weekday-weekend schedule with higher levels of negative affect in the evening-chronotype patient subgroup at weekends. Results are discussed with respect to a probably advantageous standardised clinical setting with early morning routines, especially for patients with evening chronotypes.

Evening preference and poor sleep independently affect attentional-executive functions in patients with depression.

Cognitive impairments are well documented in major depressive disorder (MDD), however, they cannot be fully explained by depressive symptom severity. We investigated how diurnal preference and sleep quality affect cognitive function in MDD. In 34 inpatients with current MDD and 29 healthy controls (HC), we obtained diurnal preference (Morningness-Eveningness Questionnaire, MEQ) and subjective sleep quality (Pittsburgh Sleep Quality Index, PSQI). Further, current mood and neuropsychological performance (Trail Making Test, TMT, part A and B) were assessed in the evening and in the following morning. Patients with MDD performed worse than HC on the TMT-B (particularly requiring executive function), but not on the TMT-A (assessing foremost visuomotor processing speed). In general, participants with evening preference (MEQ-score median split) performed poorer on the TMT than participants with morning preference. Subgroup analyses within MDD confirmed the negative effect of evening preference on the TMT. In addition, patients with severely impaired sleep quality (PSQI > 10) performed cognitively worse than patients with normal to moderately impaired sleep quality (PSQI ≤ 10). The results were largely independent of current mood state. Our findings suggest that evening preference and severely impaired sleep quality independently contribute to cognitive impairment in MDD.