title: Family study of fibromyalgia and affective spectrum disorder.
abstract: BACKGROUND
  Fibromyalgia is one member of a proposed group of psychiatric and medical disorders, collectively termed affective spectrum disorder (ASD), hypothesized to share possibly heritable pathophysiologic features. Two predictions of the ASD hypothesis were tested: ASD, taken as a single entity, aggregates in families; and fibromyalgia coaggregates with other forms of ASD in families.
  
  
  METHODS
  Probands with and without fibromyalgia, together with their first-degree relatives, were administered structured diagnostic interviews. Noninterviewed relatives were diagnosed according to information provided by interviewed relatives. Aggregation and coaggregation of disorders were analyzed with proband predictive logistic and linear regression models.
  
  
  RESULTS
  In 533 relatives of 78 probands with fibromyalgia and 272 relatives of 40 probands without fibromyalgia, the estimated odds ratio (OR) (95% confidence interval) for the familial aggregation of ASD was 1.8 (.97, 3.2), p = .065, and the increase in number of forms of ASD in a relative for each additional form of ASD in a proband was .076 (.027, .1240), p = .002. The OR for the coaggregation of fibromyalgia with other forms of ASD was 2.0 (1.2, 3.2), p = .004; this remained significant even after excluding all mood-disorder diagnoses: 1.8 (1.1, 3.0), p = .012.
  
  
  CONCLUSIONS
  These findings support familial aggregation of ASD collectively and familial coaggregation of fibromyalgia with other forms of ASD.
authors.affiliation: Biological Psychiatry Laboratory, McLean Hospital Department of Psychiatry, Harvard Medical School, Belmont, MA 02478, USA. jhudson@mclean.harvard.edu
authors.forename: James I
authors.initials: JI
authors.lastname: Hudson
authors.forename: Lesley M
authors.initials: LM
authors.lastname: Arnold
authors.forename: Paul E
authors.initials: PE
authors.lastname: Keck
authors.forename: Megan B
authors.initials: MB
authors.lastname: Auchenbach
authors.forename: Harrison G
authors.initials: HG
authors.lastname: Pope
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005190:Family; D005192:Family Health; D005260:Female; D005356:Fibromyalgia / Q000150:complications / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000150:complications / Q000453:epidemiology / Q000235:genetics*; D016017:Odds Ratio; D015995:Prevalence