title: Using multiple methods to characterize the phenotype of individuals with a family history of major depressive disorder.
abstract: BACKGROUND
  Unaffected relatives (URs) of individuals with major depressive disorder (MDD) are biologically more vulnerable to depression. We compare healthy URs and controls at the level of phenotype (symptoms and functioning) and endophenotype (negative emotion bias), and further investigate the interrelation between these and the contribution of environmental early life stress.
  
  
  METHODS
  URs (n=101), identified using Family History Screen interview methods and matched controls completed written and interview questions assessing symptoms of depression and anxiety, negative cognitive style, life functioning and early life stress. Biases in emotion processing were measured using a facial expression of emotion identification paradigm.
  
  
  RESULTS
  Compared to controls, URs reported higher levels of depression and anxiety, a stronger negative cognitive bias, and poorer functioning and lower satisfaction with life. URs were slower to correctly identify fear and sad facial expressions. A slower response time to identify sad faces was correlated with lower quality of life in the social domain. Early life stress (ELS) did not contribute significantly to any outcome.
  
  
  CONCLUSIONS
  The methodology relies on accurate reporting of participants' own psychiatric history and that of their family members. The degree of vulnerability varies among URs.
  
  
  CONCLUSIONS
  A family history of depression accounts for subtle differences in symptom levels and functioning without a necessary role of ELS. A negative emotion bias in processing emotion may be one vulnerability marker for MDD. Biological markers may affect functioning measures before symptoms at the level of experience.
authors.affiliation: Discipline of Psychiatry, University of Sydney Medical School, NSW, Australia.
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Watters
authors.forename: Ian H
authors.initials: IH
authors.lastname: Gotlib
authors.forename: Anthony W F
authors.initials: AW
authors.lastname: Harris
authors.forename: Philip M
authors.initials: PM
authors.lastname: Boyce
authors.forename: Leanne M
authors.initials: LM
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D015982:Bias; D016022:Case-Control Studies; D003071:Cognition; D003863:Depression; D003865:Major Depressive Disorder / Q000235:genetics / Q000523:psychology*; D004644:Emotions; D005239:Fear; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D013315:Stress, Psychological; D055815:Young Adult
keywords: Biomarkers; Brain research and integrative neuroscience network (BRAINnet) facial; Depression; Facial expressions of emotion; Family study; First-degree relatives