title: Depressive symptomatology is influenced by chronotypes.
abstract: BACKGROUND
  Rhythm disturbances are a frequent clinical manifestation of depression. In recent years a possible relationship between depression and chronotypes has emerged. Specifically eveningness has been proposed as vulnerability factor. The aim of this study was to describe sleep features of depressed patients according to chronotypes and to explore possible associations with the clinical features of depressive episodes.
  
  
  METHODS
  100 patients diagnosed with Major Depressive Disorder according to the Mini International Neuropsychiatric Interview (MINI) were included (age: 34+/-11.74, range: 18-60 years; female/male:79/21). At admission the Hamilton Rating Scale for Depression (HRSD) was administered. Patients were also administered the Morningness-Eveningness Questionnaire (MEQ), the Epworth Sleepiness Scale, the Athens Insomnia Scale and the Pittsburgh Sleep Quality Index.
  
  
  RESULTS
  According to MEQ scores patients were classified in three groups: a) eveningness (n=18), b) neither (n=61) and c) morningness type (n=21). The age was different among chronotypes, being morningness-type patients older. The eveningness-type group showed higher scores in suicidal thoughts, more impaired work and activities, higher paranoid symptoms, higher scores on the anxiety cluster (HRSD), while the morningness-type group showed lower proportion of melancholic symptoms (MINI). We did not find association between sleep parameters and specific chronotypes.
  
  
  CONCLUSIONS
  The relatively small sample size and the concurrent assessment of chronotypes and depression may have biased our findings.
  
  
  CONCLUSIONS
  Our data suggest the idea that chronotypes have an impact on depressive episodes features, with higher severity for the eveningness-type.
authors.affiliation: National Institute of Psychiatry, Mexico.
authors.forename: Enrique
authors.initials: E
authors.lastname: Gaspar-Barba
authors.forename: Raffaella
authors.initials: R
authors.lastname: Calati
authors.forename: Carlos S
authors.initials: CS
authors.lastname: Cruz-Fuentes
authors.forename: Martha P
authors.initials: MP
authors.lastname: Ontiveros-Uribe
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Natale
authors.forename: Diana
authors.initials: D
authors.lastname: De Ronchi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Serretti
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology; D003865:Major Depressive Disorder / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012890:Sleep / Q000502:physiology*; D055815:Young Adult