Objective: To assess the course and short-term outcomes associated with separation anxiety disorder (SAD) in a community setting. Method: The subjects were 161 of 2,061 8- to 17-year-old twins with SAD from a community-based twin study. Subjects were born between 1974 and 1983. Subjects and parents were personally interviewed about the subject's…

Objective: To examine the etiologies of covariation of childhood sleep problems and other behavioral/emotional problems in young children. Method: The parents of more than 6,000 twin pairs provided information on their twins' anxiety, conduct, and hyperactivity at ages 3, 4, and 7 by completing the Strengths and Difficulties Questionnaire.…

Objective: To study familial and nonfamilial environmental influences on attention problems and attention-deficit/hyperactivity disorder (ADHD) in monozygotic twins discordant and concordant-high and low for these traits. Method: Ninety-five twin pairs from The Netherlands Twin Register were selected. Longitudinal survey data were collected at 1,…

Objective: To determine the impact of including sluggish cognitive tempo items on the factor and latent class structure of attention-deficit/hyperactivity disorder (ADHD) subtypes in boys and girls. Method: Parent report of two sluggish cognitive tempo items on a population-based sample of 1,430 female twins and 1,414 male twins were analyzed…

Objective: To explore the genetic and environmental influences on DSM-IV conduct disorder (CD) aggressive and nonaggressive subscales, taking into account age and sex differences. Method: A community sample of 1,100 twin pairs (ages 11-18) was interviewed using the Diagnostic Interview Schedule for Children. Bivariate analyses, using variable…

Objective: To study the genetic and environmental contributions to stability and change of attention-deficit/hyperactivity disorder (ADHD) symptoms between 8 and 9 and 13 and 14 years of age. Method: The sample included 1,480 twin pairs born in Sweden between May 1985 and December 1986. At wave 1 in 1994, when twins were 8-9 years old, 1,106 (75%)…

Objective: To investigate children selected from a community sample for showing extreme autistic-like traits and to assess the degree to which these individual traits--social impairments (SIs), communication impairments (CIs), and restricted repetitive behaviors and interests (RRBIs)--are caused by genes and environments, whether all of them are…

Objective: To examine gender differences in attention-deficit/hyperactivity disorder ("ADHD") symptom comorbidity with "oppositional defiant disorder", "conduct disorder", "separation anxiety disorder", "generalized anxiety disorder", speech therapy, and remedial reading in children. Method: From…

Objective: To estimate the genetic and environmental contributions to oppositional defiant behavior (ODB) from mother, father, and teacher report using the Conners Revised Short Forms in a large twin sample. Method: ODB data were collected from 1,595 mothers, 1,114 fathers, and 793 teachers of 7-year-old twin pairs from the Netherlands Twin…

Objective: Antisocial behavior that begins in mid- to late adolescence does not fit into commonly accepted taxonomies of antisocial behavior, yet it clearly exists. This study examined how this course of antisocial behavior compares with persisting (beginning by early adolescence and continuing through late adolescence) and desisting (stopping by…