Shared genetic influences on negative emotionality and major depression/conduct disorder comorbidity

• Authors: Jennifer L. Tackett, University of Toronto; Irwin Waldman, Emory University; Carol A. Van Hulle, University of Chicago; Benjamin B. Lahey, University of Chicago
• Journal Title: Journal of the American Academy of Child and Adolescent Psychiatry
• Volume: Volume 50, Number 8
• Publisher: Elsevier: 12 months | 2011-08-01, Pages 818-827
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.jaac.2011.05.007
• Subjects: Health Sciences, Mental Health; Biology, Genetics; Psychology, Clinical
• Keywords: Adolescent; Affective Symptoms; Child; Comorbidity; Conduct Disorder; Depressive Disorder, Major; Female; Genetic Predisposition to Disease; Humans; Male; Models, Genetic; Multivariate Analysis; Sex Distribution; Tennessee

Abstract

Objective: To investigate whether genetic contributions to major depressive disorder and conduct disorder comorbidity are shared with genetic influences on negative emotionality. Method: Primary caregivers of 2,022 same- and opposite-sex twin pairs 6 to 18 years of age comprised a population-based sample. Participants were randomly selected across five regions in Tennessee, with stratification by age and geographic location. Face-to-face structured interviews were conducted with the primary caregiver of a representative sample of twins. Results: After accounting for genetic influences on negative emotionality, genetic influences on major depressive disorder/conduct disorder comorbidity were nonsignficant, but only in male twins. Specifically, 19% of the variance in the two disorders was accounted for by genetic factors shared with negative emotionality in male twins. Although the full hypothesis could not be tested in female twins, 10% to 11% of the variance in the two disorders was also accounted for by genetic factors shared with negative emotionality. Common shared environmental and nonshared environmental influences were found for major depressive disorder/conduct disorder comorbidity in male and female twins. Conclusions: Negative emotionality represents an important dispositional trait that may explain genetic influences on major depressive disorder/conduct disorder comorbidity, at least for boys. Models of major depressive disorder/conduct disorder comorbidity must simultaneously measure common and specific genetic and environmental factors for a full understanding of this phenomenon. Gender differences require specific research attention in dispositional factors and developmental progression.