title: A blind re-analysis of the Iowa family study of obsessive-compulsive disorder.
abstract: We present results from a re-analysis of the Iowa family study of obsessive-compulsive disorder (OCD) that previously concluded the disorder was not familial. These conclusions were based on Diagnostic Interview Schedule results of first-degree relatives (FDRs) and not a best estimate diagnosis (BED). For the re-analysis we reviewed raw data on OCD and control probands and their FDRs. Relatives had been assessed through structured interviews, validated questionnaires, family history, and medical records in some cases. BEDs were assigned through a blind consensus procedure employing DSM-IV criteria. The data were analyzed using logistic regression with generalized estimating equations to account for within family correlations. BEDs were assigned to 32 OCD probands, 31 control probands, and 352 FDRs, including 249 FDRs who were interviewed directly and 103 FDRs who were unavailable or deceased. Lifetime prevalence of definite/probable OCD was significantly higher in the FDRs of OCD probands than controls (10.7% vs. 3.8%, OR=3.04, p=0.026). FDRs of OCD probands had significantly higher rates of depressive illness than relatives of controls. Depression of any type in relatives was predicted by the proband's depression history. We conclude that OCD is familial. The re-analysis highlights the importance of the BED procedure in family studies.
authors.affiliation: Department of Psychiatry, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. donald-black@uiowa.edu
authors.forename: Donald W
authors.initials: DW
authors.lastname: Black
authors.forename: Amanda
authors.initials: A
authors.lastname: Stumpf
authors.forename: Brett
authors.initials: B
authors.lastname: McCormick
authors.forename: Jeff
authors.initials: J
authors.lastname: Allen
authors.forename: Nancee
authors.initials: N
authors.lastname: Blum
authors.forename: Russell
authors.initials: R
authors.lastname: Noyes
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D005190:Family / Q000523:psychology*; D005192:Family Health; D005260:Female; D006801:Humans; D007484:Iowa / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics; D015995:Prevalence; D011569:Psychiatric Status Rating Scales; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Behavioral genetics; Best estimate diagnosis; Family studies; Obsessive-compulsive disorder (OCD)