title: Structure of internalising symptoms in early adulthood.
abstract: BACKGROUND
  Debate surrounds the underlying structure of internalising disorders including major depression, generalised anxiety disorder, phobias and panic disorders.
  
  
  OBJECTIVE
  To model the within-time and across-time relationships of internalising symptoms, incorporating effects from generalised internalising and disorder-specific components of continuity.
  
  
  METHODS
  Data were gathered from a 25-year longitudinal study of a birth cohort of 953 New Zealand children. Outcome measures included DSM-IV symptom scores for major depression, generalised anxiety disorder, phobia and panic disorder at the ages of 18, 21 and 25 years.
  
  
  RESULTS
  Structural equation modelling showed that, within-times, a common underlying measure of generalised internalising explained symptom score comorbidities. Across-time correlation of symptom scores was primarily accounted for by continuity over time in generalised internalising. However, for major depression and phobia there was also evidence of across-time continuity in the disorder-specific components of symptoms.
  
  
  CONCLUSIONS
  Internalising symptoms can be partitioned into components reflecting both a generalised tendency to internalising and disorder-specific components.
authors.affiliation: Christchurch Health and Development Study, Christchurch School of Medicine and Health Sciences, PO Box 4345, Christchurch, New Zealand. david.fergusson@chmeds.ac.nz
authors.forename: David M
authors.initials: DM
authors.lastname: Fergusson
authors.forename: L John
authors.initials: LJ
authors.lastname: Horwood
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Boden
mesh_terms: D000293:Adolescent; D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000523:psychology*; D002648:Child; D002675:Child, Preschool; D003866:Depressive Disorder / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007389:Internal-External Control; D008137:Longitudinal Studies; D008297:Male; D008960:Models, Psychological; D009520:New Zealand