title: Latent Classes of Symptoms related to Clinically Depressed Mood in Adolescents.
abstract: BACKGROUND
  The diagnosis of major depressive disorder (MDD), according to theDiagnostic and Statistical Manual of Mental Disorders, is based only on adult symptomatology of depression and not adapted for age and gender. This may contribute to the low diagnostic specificity and validity of adolescent MDD. In this study, we investigated whether latent classes based on symptoms associated with depressed mood could be identified in a sample of adolescents seeking psychiatric care, regardless of traditionally defined diagnostic categories.
  
  
  METHODS
  Self-reports of the Strengths and Difficulties Questionnaire and the Development and Well-Being Assessment were collected consecutively from all new patients between the ages of 13 and 17 years at two psychiatric outpatient clinics in Stockholm, Sweden. Those who reported depressed mood at intake yielded a sample of 21 boys and 156 girls. Latent class analyses were performed for all screening items and for the depression-specific items of the Development and Well-Being Assessment.
  
  
  RESULTS
  The symptoms that were reported in association with depressed mood differentiated the adolescents into two classes. One class had moderate emotional severity scores on the Strengths and Difficulties Questionnaire and mainly symptoms that were congruent with theDiagnostic and Statistical Manual of Mental Disorderscriteria for MDD. The other class had higher emotional severity scores and similar symptoms to those reported in the first class. However, in addition, this group demonstrated more diverse symptomatology, including vegetative symptoms, suicidal ideation, anxiety, conduct problems, body dysmorphic symptoms, and deliberate vomiting. The classes predicted functional impairment in that the members of the second class showed more functional impairment.
  
  
  CONCLUSIONS
  The relatively small sample size limited the generalizability of the results of this study, and the amount of items included in the analysis was restricted by the rules of latent class analysis. No conclusions about gender differences between the classes could be could be drawn as a result of the low number of boys included in the study.
  
  
  CONCLUSIONS
  Two distinct classes were identified among adolescents with depressed mood. The class with highest emotional symptom severity score and the most functional impairment had a more diverse symptomatology that included symptoms that were not congruent with the traditional diagnostic criteria of MDD. However, this additional symptomatology is clinically important to consider. As a result, the clinical usefulness of theDiagnostic and Statistical Manual of Mental Disordersduring the diagnostic process of adolescent depression is questioned.
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Sweden ; Osher Center for Integrative Medicine, Karolinska Institutet, Sweden ; Department of Psychiatry, University of California San Francisco, USA.
authors.forename: Eva Henje
authors.initials: EH
authors.lastname: Blom
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Forsman
authors.affiliation: Osher Center for Integrative Medicine, Karolinska Institutet, Sweden.
authors.forename: Tony T
authors.initials: TT
authors.lastname: Yang
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Sweden ; Centre for Psychiatric Research and Education, Karolinska Institutet, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Serlachius
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Sweden.
authors.forename: Jan-Olov
authors.initials: JO
authors.lastname: Larsson
keywords: Adolescent major depressive disorder; Diagnostic and Statistical Manual of Mental Disorders; diagnostic validity; latent class analysis