Hot Paper in Psychiatry/Psychology

February 2014
“Genetic heritability and shared environmental factors among twin pairs with autism,” by Joachim Hallmayer, et al., JAMA Psychiatry*, 68(11): 1095-1102, November 2011.

Abstract: “Context: Autism is considered the most heritable of neurodevelopmental disorders, mainly because of the large difference in concordance rates between monozygotic and dizygotic twins. Objective: To provide rigorous quantitative estimates of genetic heritability of autism and the effects of shared environment. Design, Setting, and Participants: Twin pairs with at least 1 twin with an autism spectrum disorder (ASD) born between 1987 and 2004 were identified through the California Department of Developmental Services. Main Outcome Measures: Structured diagnostic assessments (Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule) were completed on 192 twin pairs. Concordance rates were calculated and parametric models were fitted for 2 definitions, 1 narrow (strict autism) and 1 broad (ASD). Results: For strict autism, probandwise concordance for male twins was 0.58 for 40 monozygotic pairs (95% confidence interval [CI], 0.42-0.74) and 0.21 for 31 dizygotic pairs (95% CI, 0.09-0.43); for female twins, the concordance was 0.60 for 7 monozygotic pairs (95% CI, 0.28-0.90) and 0.27 for 10 dizygotic pairs (95% CI, 0.09-0.69). For ASD, the probandwise concordance for male twins was 0.77 for 45 monozygotic pairs (95% CI, 0.65-0.86) and 0.31 for 45 dizygotic pairs (95% CI, 0.16-0.46); for female twins, the concordance was 0.50 for 9 monozygotic pairs (95% CI, 0.16-0.84) and 0.36 for 13 dizygotic pairs (95% CI, 0.11-0.60). A large proportion of the variance in liability can be explained by shared environmental factors (55%; 95% CI, 9%-81% for autism and 58%; 95% CI, 30%-80% for ASD) in addition to moderate genetic heritability (37%; 95% CI, 8%-84% for autism and 38%; 95% CI, 14%-67% for ASD). Conclusion: Susceptibility to ASD has moderate genetic heritability and a substantial shared twin environmental component."

This 2011 report from JAMA Psychiatry (*known until 2013 as Archives of General Psychiatry) was cited 23 times in current journal articles indexed by Thomson Reuters during July-August 2013. Of papers indexed by Thomson Reuters in the last two years under the main heading of Psychiatry/Psychology, no other report (aside from reviews) collected a higher number of citations during that two-month period. Prior to the most recent bimonthly count, citations to the report have accrued as follows, as tracked by Essential Science Indicators Hot Papers:

May-June 2013: 22 citations
March-April 2013: 17
January-February 2013: 16
November-December 2012: 16
September-October 2012: 10
July-August 2012: 7
May-June 2012: 13
March-April 2012: 6
January-February 2012: 2
November-December 2011: 2

Total citations to date: 134

SOURCE: Thomson Reuters Web of Science

The data and citation records included in this report are from Thomson Reuters Web of ScienceTM. Web of ScienceTM is a registered trademark of Thomson Reuters. All rights reserved.