Shared genetic and environmental influences on early temperament and preschool psychiatric disorders in Hispanic twins.
OBJECTIVE
Despite an increasing recognition that psychiatric disorders can be diagnosed as early as preschool, little is known how early genetic and environmental risk factors contribute to the development of psychiatric disorders during this very early period of development.


METHODS
We assessed infant temperament at age 1, and attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and separation anxiety disorder (SAD) at ages 3 through 5 years in a sample of Hispanic twins. Genetic, shared, and non-shared environmental effects were estimated for each temperamental construct and psychiatric disorder using the statistical program MX. Multivariate genetic models were fitted to determine whether the same or different sets of genes and environments account for the co-occurrence between early temperament and preschool psychiatric disorders.


RESULTS
Additive genetic factors accounted for 61% of the variance in ADHD, 21% in ODD, and 28% in SAD. Shared environmental factors accounted for 34% of the variance in ODD and 15% of SAD. The genetic influence on difficult temperament was significantly associated with preschool ADHD, SAD, and ODD. The association between ODD and SAD was due to both genetic and family environmental factors. The temperamental trait of resistance to control was entirely accounted for by the shared family environment.


CONCLUSIONS
There are different genetic and family environmental pathways between infant temperament and psychiatric diagnoses in this sample of Puerto Rican preschool age children.
Virginia Institute for Psychiatric and Behavioral Genetics,Department of Human and Molecular Genetics,Virginia Commonwealth University,Richmond,VA,USA.
Judy L
JL
Silberg
Virginia Institute for Psychiatric and Behavioral Genetics,Department of Human and Molecular Genetics,Virginia Commonwealth University,Richmond,VA,USA.
Nathan
N
Gillespie
Virginia Institute for Psychiatric and Behavioral Genetics,Department of Human and Molecular Genetics,Virginia Commonwealth University,Richmond,VA,USA.
Ashlee A
AA
Moore
Virginia Institute for Psychiatric and Behavioral Genetics,Department of Human and Molecular Genetics,Virginia Commonwealth University,Richmond,VA,USA.
Lindon J
LJ
Eaves
Department of Psychological and Brain Sciences,Indiana University Bloomington,Indiana,USA.
John
J
Bates
Virginia Institute for Psychiatric and Behavioral Genetics,Department of Human and Molecular Genetics,Virginia Commonwealth University,Richmond,VA,USA.
Steven
S
Aggen
Virginia Institute for Psychiatric and Behavioral Genetics,Department of Human and Molecular Genetics,Virginia Commonwealth University,Richmond,VA,USA.
Elizabeth
E
Pfister
Behavioral Sciences Research Institute,University of Puerto Rico Medical SciencesCampus,San Juan,Puerto Rico.
Glorisa
G
Canino
D001010:Anxiety, Separation / Q000235:genetics / Q000503:physiopathology / Q000523:psychology; D001289:Attention Deficit Disorder with Hyperactivity / Q000235:genetics / Q000503:physiopathology / Q000523:psychology; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000235:genetics / Q000503:physiopathology / Q000523:psychology; D002675:Child, Preschool; D005260:Female; D059647:Gene-Environment Interaction; D006630:Hispanic or Latino / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D019655:Quantitative Trait, Heritable; D013694:Temperament; D014427:Twins / Q000235:genetics*
twins