title: Birth order in obsessive-compulsive disorder.
abstract: Birth order and family size were studied in 392 cases of obsessive-compulsive disorder (OCD) seen in the decade 1975-84. On the basis of Slater's index, there was a nonsignificant excess of earlier-born children in the sample. However, this excess was not present in each individual family size, and was not due to either age of onset or sex. Smaller families had more earlier-born index cases, and larger families had more later-born index cases. First-born and only children were not overrepresented in the sample.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001722:Birth Order; D002648:Child; D005191:Family Characteristics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000235:genetics*; D012737:Sex Factors