title: Relationships of neuroticism and extraversion with axis I and II comorbidity among patients with DSM-IV major depressive disorder.
abstract: BACKGROUND
  High comorbidity with axis I and II disorders among major depressive disorder (MDD) patients may in part be due to the predisposing personality dimensions of neuroticism and extraversion. However, a comprehensive view of this relationship is lacking.
  
  
  METHODS
  MDD patients (n=193) in the Vantaa Depression Study were interviewed at baseline and at 6 and 18 months with the SCAN and SCID-II, and a general population comparison group (n=388) surveyed by mail. Neuroticism and extraversion were measured with the Eysenck Personality Inventory. A dose-exposure relationship between standardized levels of neuroticism and extraversion and type and number of comorbid axis I and II disorders among patients with MDD was hypothesized.
  
  
  RESULTS
  Prevalence and number of comorbid axis I and II disorders increased significantly with increasing level of neuroticism. In contrast, as the level of extraversion increased, the prevalences of social phobia and cluster C personality disorders decreased. Patients with pure MDD or with any comorbid axis I or II disorder had z-scores of neuroticism of +0.46, +0.90 and +1.30 and of extraversion of -0.34, -0.47 and -0.84, respectively.
  
  
  CONCLUSIONS
  Patients' personality scores were not pre-morbid.
  
  
  CONCLUSIONS
  Among MDD patients, a positive dose-exposure relationship appears to exist between neuroticism and prevalence and number of comorbid axis I and II disorders. A negative relationship exists between level of extraversion and prevalence of social phobia and cluster C personality disorders. These findings are consistent with the hypothesis that high neuroticism and low extraversion predispose to comorbid axis I and II disorders among patients with MDD.
authors.affiliation: Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Jylhä
authors.forename: Tarja
authors.initials: T
authors.lastname: Melartin
authors.forename: Erkki
authors.initials: E
authors.lastname: Isometsä
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001008:Anxiety Disorders / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005120:Extraversion, Psychological; D005260:Female; D005387:Finland; D005500:Follow-Up Studies; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D009497:Neurotic Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D010554:Personality Disorders / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D010555:Personality Inventory; D010698:Phobic Disorders / Q000453:epidemiology; D015995:Prevalence; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors