title: Intra- and inter-individual variability of longitudinal daytime melatonin secretion patterns in depressed and non-depressed individuals.
abstract: Disrupted melatonin secretion is regarded as a link between circadian rhythm and major depression, but results have been contradictory. We hypothesize that this might be due to averaging across individuals and too short measurements periods. In this study, pair-matched depressed and non-depressed individuals sampled their saliva three times a day, 30 days, in their natural environment. The depressed group showed significantly more variance and higher melatonin levels (p < 0.05). Substantial interindividual heterogeneity and day-to-day variability was found. The individual time-series approach allowed us to reveal this variability. Important information remains unnoticed when analyzing melatonin only at the group level.
authors.affiliation: Interdisciplinary Center of Psychopathology and Emotion Regulation, University Medical Center Groningen, University of Groningen , Groningen , The Netherlands and.
authors.forename: Maria E J
authors.initials: ME
authors.lastname: Bouwmans
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Bos
authors.forename: Sanne H
authors.initials: SH
authors.lastname: Booij
authors.forename: Martijn
authors.initials: M
authors.lastname: van Faassen
authors.forename: Albertine J
authors.initials: AJ
authors.lastname: Oldehinkel
authors.forename: Peter
authors.initials: P
authors.lastname: de Jonge
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D003865:Major Depressive Disorder / Q000378:metabolism*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008550:Melatonin / Q000096:biosynthesis / Q000378:metabolism*; D008875:Middle Aged; D012463:Saliva / Q000378:metabolism*; D013997:Time Factors
chemical_list: D008550:Melatonin
keywords: Individual differences; longitudinal studies; major depressive disorder; melatonin; saliva