With the potential to unite population health and neurobiology around a coherent, unified approach to understanding how environmental exposures “get under the skin” to produce psychiatric phenotypes, epigenetic approaches to psychopathology have tremendous potential. However, as we outline above, realizing this potential is contingent upon moving beyond several methodological challenges in the field. Broadly, investigators must be aware of the strengths and weaknesses of the study designs they employ. While designs such as disease-discordant monozygotic twin studies have useful properties that facilitate causal inference, they do not solve all problems with confounding and may not be generalizable to singletons. Care must be taken to carefully interpret findings accordingly.
