In 2000, Kenneth Kendler, M.D., received a Distinguished Investigator Grant to pioneer studies on identifying gene-environment interactions linked to the development of mental illness. He conducted a pilot study aimed at clarifying the role of environmental risk factors in major depression. The results of this research demonstrated for the first time that environmental risk factors impact genetic expression to cause major depression. This work launched the development of the field of research now known as “epigenetics,” where scientists seek to identify gene-environment interactions and their links to the development of illness.

Dr. Kendler worked with data from a longitudinal study with 9-year data on almost 2,000 female twins, “discordant” for major depression (i.e. one member of the twin pair had major depression, the other did not). He sought to identify unique environmental risk factors associated with depression since both twins were matched in genetic and familial-environmental background. In-depth life event history interviews were conducted to investigate environmental risk factors; developmental histories were acquired about mothers still alive, and pilot hormonal and imaging studies were obtained on a small subset of the twins.  



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