title: Symptom-specific course trajectories and their determinants in primary care patients with Major Depressive Disorder: Evidence for two etiologically distinct prototypes.
abstract: BACKGROUND
  The course-heterogeneity of Major Depressive Disorder (MDD) hampers development of better prognostic models. Although latent class growth analyses (LCGA) have been used to explain course-heterogeneity, such analyses have failed to also account for symptom-heterogeneity of depressive symptoms. Therefore, the aim was to identify more specific data-driven subgroups based on patterns of course-trajectories on different depressive symptom domains.
  
  
  METHODS
  In primary care MDD patients (n=205), the presence of the MDD criterion symptoms was determined for each week during a year. Weekly 'mood/cognition' (MC) and 'somatic' (SOM) scores were computed and parallel processes-LCGA (PP-LCGA) was used to identify subgroups based on the course on these domains. The classes׳ associations with baseline predictors and 2-/3-year outcomes were investigated.
  
  
  RESULTS
  PP-LCGA identified four classes: quick recovery, persisting SOM, persisting MC, and persisting SOM+MC (chronic). Persisting SOM was specifically predicted by higher baseline somatic symptomatology and somatization, and was associated with more somatic depressive symptomatology at long-term follow-up. Persisting MC was specifically predicted by higher depressive severity, thinking insufficiencies, neuroticism, loneliness and lower self-esteem, and was associated with lower mental health related quality of life and more mood/cognitive depressive symptomatology at follow-up.
  
  
  CONCLUSIONS
  The sample was small and contained only primary care MDD patients. The weekly depression assessments were collected retrospectively at 3-month intervals.
  
  
  CONCLUSIONS
  The results indicate that there are two specific prototypes of depression, characterized by either persisting MC or persisting SOM, which have different sets of associated prognostic factors and long-term outcomes, and could have different etiological mechanisms.
authors.affiliation: University of Groningen, Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Centre Groningen (UMCG), Groningen, The Netherlands. Electronic address: k.j.wardenaar@umcg.nl.
authors.forename: K J
authors.initials: KJ
authors.lastname: Wardenaar
authors.affiliation: University of Groningen, Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Centre Groningen (UMCG), Groningen, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Monden
authors.affiliation: University of Amsterdam, Department of Clinical Psychology, The Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: Conradi
authors.affiliation: University of Groningen, Interdisciplinary Center Psychopathology and Emotion Regulation (ICPE), University Medical Centre Groningen (UMCG), Groningen, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: de Jonge
mesh_terms: D000328:Adult; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D011320:Primary Health Care; D011379:Prognosis; D011788:Quality of Life / Q000523:psychology; D063189:Symptom Assessment
keywords: Depression; Dimensions; Latent class growth analysis; Persistence; Prototypes; Subtypes