Hostname: page-component-7c8c6479df-995ml Total loading time: 0 Render date: 2024-03-29T10:43:24.632Z Has data issue: false hasContentIssue false

Crying Without a Cause and Being Easily Upset in Two-Year-Olds: Heritability and Predictive Power of Behavioral Problems

Published online by Cambridge University Press:  21 February 2012

Maria M. Groen-Blokhuis*
Affiliation:
Department of Biological Psychology, VU University Amsterdam, the Netherlands. m.m.groen-blokhuis@vu.nl
Christel M. Middeldorp
Affiliation:
Department of Biological Psychology, VU University Amsterdam, the Netherlands; Department of Child and Adolescent Psychiatry, Academic Medical Center, Amsterdam, the Netherlands; Department of Child and Adolescent Psychiatry, GGZ inGeest / VU Medical Center, Amsterdam, the Netherlands.
Catharina E. M. van Beijsterveldt
Affiliation:
Department of Biological Psychology, VU University Amsterdam, the Netherlands.
Dorret I. Boomsma
Affiliation:
Department of Biological Psychology, VU University Amsterdam, the Netherlands.
*
*ADDRESS FOR CORRESPONDENCE: Maria Groen-Blokhuis, VU University, Department of Biological Psychology, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

In order to estimate the influence of genetic and environmental factors on ‘crying without a cause’ and ‘being easily upset’ in 2-year-old children, a large twin study was carried out. Prospective data were available for ~18,000 2-year-old twin pairs from the Netherlands Twin Register. A bivariate genetic analysis was performed using structural equation modeling in the Mx software package. The influence of maternal personality characteristics and demographic and lifestyle factors was tested to identify specific risk factors that may underlie the shared environment of twins. Furthermore, it was tested whether crying without a cause and being easily upset were predictive of later internalizing, externalizing and attention problems. Crying without a cause yielded a heritability estimate of 60% in boys and girls. For easily upset, the heritability was estimated at 43% in boys and 31% in girls. The variance explained by shared environment varied between 35% and 63%. The correlation between crying without a cause and easily upset (r = .36) was explained both by genetic and shared environmental factors. Birth cohort, gestational age, socioeconomic status, parental age, parental smoking behavior and alcohol use during pregnancy did not explain the shared environmental component. Neuroticism of the mother explained a small proportion of the additive genetic, but not of the shared environmental effects for easily upset. Crying without a cause and being easily upset at age 2 were predictive of internalizing, externalizing and attention problems at age 7, with effect sizes of .28–.42. A large influence of shared environmental factors on crying without a cause and easily upset was detected. Although these effects could be specific to these items, we could not explain them by personality characteristics of the mother or by demographic and lifestyle factors, and we recognize that these effects may reflect other maternal characteristics. A substantial influence of genetic factors was found for the two items, which are predictive of later behavioral problems.

Type
Articles
Copyright
Copyright © Cambridge University Press 2011