title: The time has come to stop rotations for the identification of structures in the Hamilton Depression Scale (HAM-D₁₇).
abstract: OBJECTIVE
  To use principal component analysis (PCA) to test the hypothesis that the items of the Hamilton Depression Scale (HAM-D₁₇) have been selected to reflect depression disability, whereas some of the items are specific for sub-typing depression into typical vs. atypical depression.
  
  
  METHODS
  Our previous study using exploratory factor analysis on HAM-D₁₇ has been re-analyzed with PCA and the results have been compared to a dataset from another randomized prospective study.
  
  
  RESULTS
  PCA showed that the first principal component was a general factor covering depression disability with factor loadings very similar to those obtained in the STAR*D study. The second principal component was a bi-directional factor contrasting typical vs. atypical depression symptoms. Varimax rotation gave no new insight into the factor structure of HAM-D₁₇.
  
  
  CONCLUSIONS
  With scales like the HAM-D₁₇, it is very important to make a proper clinical interpretation of the PCA before attempting any form of exploratory factor analysis. For the HAM-D₁₇, our results indicate that profile scores are needed because the total score of all 17 items in the HAM-D₁₇ does not give sufficient information.
authors.affiliation: Psychiatric Research Unit, Frederiksborg General Hospital, Copenhagen University, Hillerød, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Bech
authors.affiliation: Psychiatric Research Unit, Frederiksborg General Hospital, Copenhagen University, Hillerød, Denmark.
authors.forename: Claudio
authors.initials: C
authors.lastname: Csillag
authors.affiliation: Psychiatric Research Unit, Frederiksborg General Hospital, Copenhagen University, Hillerød, Denmark.
authors.forename: Lone
authors.initials: L
authors.lastname: Hellström
authors.affiliation: Departamento de Psiquiatria e Medicina Legal, Universidade Federal do Rio Grande do Sul (UFRGS), Porto AlegreRS, Brazil.
authors.forename: Marcelo Pio de Almeida
authors.initials: MP
authors.lastname: Fleck
mesh_terms: D003863:Depression / Q000175:diagnosis* / Q000523:psychology; D003866:Depressive Disorder / Q000175:diagnosis* / Q000523:psychology; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D025341:Principal Component Analysis; D011569:Psychiatric Status Rating Scales