title: Childhood depression subscales using repeated sessions on Children's Depression Rating Scale - revised (CDRS-R) scores.
abstract: BACKGROUND
  Although acute treatments have been shown to be effective in treating early-onset depression, only one-third or thereabouts reach a remission within 3 months. Unfortunately, delayed time to remission in early-onset depression leads to poorer therapeutic outcomes. Clearly, there is a need to identify, diagnose, and provide effective treatment of a depressed patient quickly. A sophisticated understanding of depression subscales and their change over time with treatment could enhance pathways to individualized treatment approaches for childhood depression.
  
  
  OBJECTIVE
  Previous studies have found that the clinician-measured instrument, Children's Depression Rating Scale-Revised (CDRS-R) measures multiple subscales (or components) of depression. The aim of this study was to see how these subscales may change over the course of a 12-week study. This knowledge will help determine if dimensions/subscales of childhood depression (paralleling the adult literature) using the subscales derived from factor analysis procedure is useful.
  
  
  METHODS
  We examined two clinical trials in which youth (n=234) with major depressive disorder (MDD) were treated openly with fluoxetine for eight sessions spread over 12 weeks. The CDRS-R was completed based on clinician interviews with parent and child at each session. Classical test theory and component analysis with associated parallel analysis (oblique rotation) were conducted on each week's scores.
  
  
  RESULTS
  Although more factors were needed for the baseline and first two therapy sessions, a two-factor solution sufficed thereafter. Depressed facial affect, listless speech, and hypoactivity best defined Factor I, whereas sleep problems, appetite disturbance, physical symptoms, irritability, guilt, and weeping best defined Factor II. All other symptoms cross-loaded almost equally on the two factors. The scale's reliability (internal consistency) improved from baseline to exit sessions (α=0.65-0.91). As a result, the clinicians' assessments of the various symptoms became more highly related to one another. This caused the first eigenvalue to increase from 3.24 to 7.38 and the variance explained to increase (%) from 19% to 43% over sessions. These two factors may reflect 1) clinician-observed signs and 2) reported symptoms of depression.
  
  
  CONCLUSIONS
  Factor analysis of CDRS-R data in a single session consistently generates a complex and difficult to interpret structure of at least three factors. This makes it very difficult to understand what these factors measure. However, when gathered over additional sessions, the CDRS-R structure tends to simplify to two factors. The reasons for this simplification are as yet unclear and in need of further study.
authors.affiliation: 1 Department of Psychiatry, University of Texas Southwestern Medical Center , Dallas Texas.
authors.forename: Ameena
authors.initials: A
authors.lastname: Isa
authors.forename: Ira
authors.initials: I
authors.lastname: Bernstein
authors.forename: Madhukar
authors.initials: M
authors.lastname: Trivedi
authors.forename: Taryn
authors.initials: T
authors.lastname: Mayes
authors.forename: Betsy
authors.initials: B
authors.lastname: Kennard
authors.forename: Graham
authors.initials: G
authors.lastname: Emslie
mesh_terms: D000293:Adolescent; D002648:Child; D003865:Major Depressive Disorder / Q000188:drug therapy* / Q000503:physiopathology; D005163:Factor Analysis, Statistical; D005260:Female; D005473:Fluoxetine / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D005473:Fluoxetine; D017367:Selective Serotonin Reuptake Inhibitors