a1 King's College London
a2 Yale University
As studies of measured gene–environment interactions (G × E) in developmental psychopathology gain momentum, methods for systematically and quantitatively summarizing effects across multiple studies are urgently needed. Meta-analyses of G × E findings are critical for evaluating the overall statistical and theoretical significance of any given G × E based on cumulative and systematically combined knowledge. Although meta-analytic methods for the combination of study findings based on single effect measures such as odds ratios and mean differences are well established, equivalent methods for the meta-analysis of studies investigating interactions are not well developed. This article describes one simple approach to the meta-analysis of G × E effects using, as a contemporaneous example, the interaction of the monoamine oxidase A (MAOA) gene and the impact of childhood maltreatment on risk for developing antisocial behavior.
c1 Address correspondence and reprint requests to: Alan Taylor, Social, Genetic and Developmental Psychiatry Centre, Box Number PO80, Institute of Psychiatry, King's College London, De Crespigny Park, Denmark Hill, London SE5 8AF, UK; E-mail: A.Taylor@iop.kcl.ac.uk.
We express our thanks to the authors who assisted us in preparing our meta-analysis by providing supplementary results from their published articles: Giovanni Frazzetto, John K. Hewitt, David Huizinga, Kent W. Nilsson, and Cathy S. Widom.