title: The Major Depressive Disorder Hierarchy: Rasch Analysis of 6 items of the Hamilton Depression Scale Covering the Continuum of Depressive Syndrome.
abstract: OBJECTIVE
  Melancholic features of depression (MFD) seem to be a unidimensional group of signs and symptoms. However, little importance has been given to the evaluation of what features are related to a more severe disorder. That is, what are the MFD that appear only in the most depressed patients. We aim to demonstrate how each MFD is related to the severity of the major depressive disorder.
  
  
  METHODS
  We evaluated both the Hamilton depression rating scale (HDRS-17) and its 6-item melancholic subscale (HAM-D6) in 291 depressed inpatients using Rasch analysis, which computes the severity of each MFD. Overall measures of model fit were mean (±SD) of items and persons residual = 0 (±1); low χ2 value; p>0.01.
  
  
  RESULTS
  For the HDRS-17 model fit, mean (±SD) of item residuals = 0.35 (±1.4); mean (±SD) of person residuals = -0.15 (±1.09); χ2 = 309.74; p<0.00001. For the HAM-D6 model fit, mean (±SD) of item residuals = 0.5 (±0.86); mean (±SD) of person residuals = 0.15 (±0.91); χ2 = 56.13; p = 0.196. MFD ordered by crescent severity were depressed mood, work and activities, somatic symptoms, psychic anxiety, guilt feelings, and psychomotor retardation.
  
  
  CONCLUSIONS
  Depressed mood is less severe, while guilt feelings and psychomotor retardation are more severe MFD in a psychiatric hospitalization. Understanding depression as a continuum of symptoms can improve the understanding of the disorder and may improve its perspective of treatment.
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.|Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.|Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento, Porto Alegre, Brazil.
authors.forename: Lucas
authors.initials: L
authors.lastname: Primo de Carvalho Alves
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.|Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.|Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento, Porto Alegre, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Pio de Almeida Fleck
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Boni
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.|Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.|Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento, Porto Alegre, Brazil.
authors.forename: Neusa
authors.initials: N
authors.lastname: Sica da Rocha
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales