title: Directional and fluctuating asymmetry in finger and a-b ridge counts in psychosis: a case-control study.
abstract: BACKGROUND
  Several studies have reported alterations in finger and a-b ridge counts, and their derived measures of asymmetry, in schizophrenia compared to controls. Because ridges are fully formed by the end of the second trimester, they may provide clues to disturbed early development. The aim of this study was to assess these measures in a sample of patients with psychosis and normal controls.
  
  
  METHODS
  Individuals with psychosis (n = 240), and normal controls (n = 228) were drawn from a catchment-area case-control study. Differences in finger and a-b ridge count and Fluctuating Asymmetry were assessed in three group comparisons (non-affective psychosis versus controls; affective psychosis versus controls; non-affective psychosis versus affective psychosis). The analyses were performed separately for males and females.
  
  
  RESULTS
  There were no significant group differences for finger nor a-b ridge counts. While there were no group difference for Directional Asymmetry, for Fluctuating Asymmetry measures men with non-affective psychosis had significantly higher fluctuating asymmetry of the index finger ridge count (a) when compared to controls (FA-correlation score, p = 0.02), and (b) when compared to affective psychosis (adjusted FA-difference score, p = 0.04).
  
  
  CONCLUSIONS
  Overall, measures of finger and a-b ridge counts, and their derived measures of directional and fluctuating asymmetry were not prominent features of psychosis in this sample. While directional asymmetry in cerebral morphology is reduced in schizophrenia, this is not reflected in dermatoglyphic variables.
authors.affiliation: Queensland Centre for Schizophrenia Research, The Park Centre for Mental Health, Wacol, Qld 4076, Australia. sukanta_saha@qcsr.uq.edu.au
authors.forename: Sukanta
authors.initials: S
authors.lastname: Saha
authors.forename: Danuta
authors.initials: D
authors.lastname: Loesch
authors.forename: David
authors.initials: D
authors.lastname: Chant
authors.forename: Joy
authors.initials: J
authors.lastname: Welham
authors.forename: Ossama
authors.initials: O
authors.lastname: El-Saadi
authors.forename: Lourdes
authors.initials: L
authors.lastname: Fañanás
authors.forename: Bryan
authors.initials: B
authors.lastname: Mowry
authors.forename: John
authors.initials: J
authors.lastname: McGrath
mesh_terms: D000341:Affective Disorders, Psychotic / Q000175:diagnosis; D016022:Case-Control Studies; D003878:Dermatoglyphics; D005385:Fingers / Q000033:anatomy & histology; D007839:Functional Laterality; D006225:Hand / Q000033:anatomy & histology; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011618:Psychotic Disorders / Q000175:diagnosis*; D012559:Schizophrenia / Q000175:diagnosis