H. Gjone et Ts. Novik, PARENTAL RATINGS OF BEHAVIOR PROBLEMS - A TWIN AND GENERAL-POPULATIONCOMPARISON, Journal of child psychology and psychiatry and allied disciplines, 36(7), 1995, pp. 1213-1224
Generalization from twin studies relies on the assumption that liabili
ty to develop the disorder which is studied is influenced by similar f
actors in twins and singletons. The present study examines the impact
of pre- and perinatal factors on parental reports of behaviour problem
s in 1832 twins, and compares level of attention problems, internalizi
ng and externalizing behaviour in the twins with 723 children and adol
escents from a general population sample. The modest influence of rela
tive birth weight and birth order on level of attention problems in tw
ins did not contribute to significant differences between twins and th
e general population sample. The levels of attention problems and exte
rnalizing behaviour was similar and there was a modest age dependent d
ifference in internalizing behaviour. An increased variance was found
for externalizing behaviour in twins.