Abstract
The equal environments assumption (EEA) of the twin method posits that environmental influences that are etiologically relevant to a given phenotype are no more likely to be shared by monozygotic (MZ) than dizygotic (DZ) twin pairs. One method of testing the EEA is to evaluate whether increased rearing environment similarity in MZ twin pairs compared to DZ twin pairs is related to increased phenotypic correlation. In a sample of 885 twin pairs, we contrasted similarity in rearing environment between MZ and DZ twin pairs, examined the correlation between similarity in rearing environment and conduct disorder (CD), oppositional-defiant disorder (ODD), inattention, and hyperactivity-impulsivity symptom dimensions, and tested the effects of differential similarity in rearing environments between MZ and DZ twin pairs by testing whether rearing environment similarity moderated the correlations for the externalizing symptom dimensions. We found that MZ twins experienced substantially more similar rearing environments than DZ twins, but that there was little evidence that MZ and DZ correlations for the externalizing symptom dimensions varied by rearing environment similarity. Thus, these results constitute evidence for the validity of the EEA for childhood externalizing disorders.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
American Psychiatric Association (2000) Diagnostic and statistical manual of mental disorders (text rev), 4th edn. APA, Washington DC
Borkenau P, Riemann R, Angleitner A, Spinath FM (2002) Similarity of childhood experiences and personality resemblance in monozygotic and dizygotic twins: a test of the equal environments assumption. Personal Individ Differ 33(2):261–269
Clifford CA, Hopper JL, Fulker DW, Murray RM, Rao DC (1984) A genetic and environmental analysis of a twin family study of alcohol use, anxiety, and depression. Genet Epidemiol 1(1):63–79
Conley D, Rauscher E, Dawes C, Magnusson PK, Siegal ML (2013) Heritability and the equal environments assumption: evidence from multiple samples of misclassified twins. Behav Genet 43(5):415–426
Cronk NJ, Slutske WS, Madden PA, Bucholz KK, Reich W, Heath AC (2002) Emotional and behavioral problems among female twins: an evaluation of the equal environments assumption. J Am Acad Child Adolesc Psychiatry 41(7):829–837
Derks EM, Dolan CV, Boomsma DI (2006) A test of the equal environment assumption (EEA) in multivariate twin studies. Twin Res Hum Genet 9(03):403–411
Eley TC, Lichtenstein P, Stevenson J (1999) Sex differences in the etiology of aggressive and nonaggressive antisocial behavior: results from two twin studies. Child Dev 70(1):155–168
Eriksson M, Rasmussen F, Tynelius P (2006) Genetic factors in physical activity and the equal environment assumption–the Swedish young male twins study. Behav Genet 36(2):238–247
Ficks CA, Lahey BB, Waldman ID (2013) Does low birth weight share common genetic or environmental risk with childhood disruptive disorders? J Abnorm Psychol 122(3):842
Goodman R, Stevenson J (1989) A twin study of hyperactivity—II. The aetiological role of genes, family relationships and perinatal adversity. J Child Psychol Psychiatry 30(5):691–709
Greven CU, Rijsdijk FV, Plomin R (2011) A twin study of ADHD symptoms in early adolescence: hyperactivity-impulsivity and inattentiveness show substantial genetic overlap but also genetic specificity. J Abnorm Child Psychol 39(2):265–275
Heath AC, Jardine R, Martin NG (1989) Interactive effects of genotype and social environment on alcohol consumption in female twins. J Stud Alcohol Drugs 50(01):38
Herjanic B, Reich W (1982) Development of a structured psychiatric interview for children: agreement between child and parent on individual symptoms. J Abnorm Child Psychol 10(3):307–324
Hettema JM, Neale MC, Kendler KS (1995) Physical similarity and the equal-environment assumption in twin studies of psychiatric disorders. Behav Genet 25(4):327–335
Jackson RW, Snieder H, Davis H, Treiber FA (2001) Determination of twin zygosity: a comparison of DNA with various questionnaire indices. Twin Res 4(1):12–18
Kaprio J, Koskenvuo M, Rose RJ (1990) Change in cohabitation and intrapair similarity of monozygotic (MZ) cotwins for alcohol use, extraversion, and neuroticism. Behav Genet 20(2):265–276
Kendler KS (1983) Overview: a current perspective on twin studies of schizophrenia. Am J Psychiatry 140(11):1413–1425
Kendler KS, Gardner CO (1998) Twin studies of adult psychiatric and substance dependence disorders: are they biased by differences in the environmental experiences of monozygotic and dizygotic twins in childhood and adolescence? Psychol Med 28(03):625–633
Kendler KS, Heath A, Martin NG, Eaves LJ (1986) Symptoms of anxiety and depression in a volunteer twin population: the etiologic role of genetic and environmental factors. Arch Gen Psychiatry 43(3):213–221
Kendler KS, Neale MC, Kessler RC, Heath AC, Eaves LJ (1993) A test of the equal-environment assumption in twin studies of psychiatric illness. Behav Genet 23(1):21–27
Kendler KS, Neale MC, Kessler RC, Heath AC, Eaves LJ (1994) Parental treatment and the equal environment assumption in twin studies of psychiatric illness. Psychol Med 24(03):579–590
Klump KL, Holly A, Iacono WG, McGue M, Willson LE (2000) Physical similarity and twin resemblance for eating attitudes and behaviors: a test of the equal environments assumption. Behav Genet 30(1):51–58
Koenig LB, Jacob T, Haber JR, Xian H (2010) Testing the equal environments assumption in the children of twins design. Behav Genet 40(4):533–541
Larsson H, Asherson P, Chang Z, Ljung T, Friedrichs B, Larsson JO, Lichtenstein P (2013) Genetic and environmental influences on adult attention deficit hyperactivity disorder symptoms: a large Swedish population-based study of twins. Psychol Med 43(01):197–207
Lewontin RC, Rose SPR, Kamin LJ (1984) Not in our genes: biology, ideology, and human nature. Pantheon Books, New York
Loehlin JC, Nichols RC (1976) Heredity, environment, and personality: A study of 850 sets of twins. University of Texas Press, Austin
Lytton H (1977) Do parents create, or respond to, differences in twins? Dev Psychol 13(5):456–459
Martin NG, Eaves LJ, Heath AC, Jardine R, Feingold LM, Eysenck HJ (1986) Transmission of social attitudes. Proc Natl Acad Sci 83(12):4364–4368
Matheny AP Jr (1979) Appraisal of parental bias in twin studies. Ascribed zygosity and IQ differences in twins. Acta Geneticae Medicae et Gemellologiae 28(2):155–160
Matheny AP Jr, Wilson RS, Dolan AB (1976) Relations between twins’ similarity of appearance and behavioral similarity: testing an assumption. Behav Genet 6(3):343–351
Morris-Yates A, Andrews G, Howie P, Henderson S (1990) Twins: a test of the equal environments assumption. Acta Psychiatr Scand 81(4):322–326
Munsinger H, Douglass A (1976) The syntactic abilities of identical twins, fraternal twins, and their siblings. Child Dev 47(1):40–50
Plomin R, Willerman L, Loehlin JC (1976) Resemblance in appearance and the equal environments assumption in twin studies of personality traits. Behav Genet 6(1):43–52
Rhee SH, Waldman ID (2002) Genetic and environmental influences on antisocial behavior: a meta-analysis of twin and adoption studies. Psychol Bull 128:490–529
Rhee SH, Waldman ID, Hay DA, Levy F (1999) Sex differences in genetic and environmental influences on DSM-III-R attention deficit hyperactivity disorder (ADHD). J Abnorm Psychol 108:24–41
Saudino KJ, Ronald A, Plomin R (2005) The etiology of behavior problems in 7-year-old twins: substantial genetic influence and negligible shared environmental influence for parent ratings and ratings by same and different teachers. J Abnorm Child Psychol 33(1):113–130
Scarr S (1968) Environmental bias in twin studies. Biodemogr Soc Biol 15(1):34–40
Scarr S, Carter-Saltzman L (1979) Twin method: defense of a critical assumption. Behav Genet 9(6):527–542
Spitz E, Moutier R, Reed T, Busnel MC, Marchaland C, Roubertoux PL, Carlier M (1996) Comparative diagnoses of twin zygosity by SSLP variant analysis, questionnaire, and dermatoglyphic analysis. Behav Genet 26(1):55–63
Sullivan PF, Bulik CM, Kendler KS (1998) The epidemiology and classification of bulimia nervosa. Psychol Med 28(3):599–610
Waldman ID, Rowe DC, Abramowitz A, Kozel ST, Mohr JH, Sherman SL et al (1998) Association and linkage of the dopamine transporter gene and attention-deficit hyperactivity disorder in children: Heterogeneity owing to diagnostic subtype and severity. Am J Hum Genet 63(6):1767–1776
Wyatt WJ, Midkiff DM (2006) Biological psychiatry: a practice in search of a science. Behav Soc Issues 15(2):132–151
Xian H, Chantarujikapong SI, Scherrer JF, Eisen SA, Lyons MJ, Goldberg J et al (2000) Genetic and environmental influences on posttraumatic stress disorder, alcohol and drug dependence in twin pairs. Drug Alcohol Depend 61(1):95–102
Conflict of interest
Devon LoParo and Irwin Waldman declare that they have no conflicts of interest.
Human and Animal Rights and Informed Consent
All procedures were followed in accordance with the ethical standards of the Emory University IRB committee and with the Helinski Declaration of 1975, as revised in 2000. Informed consent was obtained from all participants for being included in the study.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
LoParo, D., Waldman, I. Twins’ Rearing Environment Similarity and Childhood Externalizing Disorders: A Test of the Equal Environments Assumption. Behav Genet 44, 606–613 (2014). https://doi.org/10.1007/s10519-014-9685-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10519-014-9685-3