Moreover, future studies will need to consider more deeply the potentially confounding effects of genotype, as it is plausible that there may be confounding by allele variant. Similarly, epigenetic studies should measure epigenetic modification at more than one point in time. In order to establish epigenetic modification as a mediator between environmental exposure and an outcome of interest, this modification must occur after the environmental exposure and prior to the outcome. In this way, future studies should employ prospective cohort designs that allow for regular, periodic assessment of epigenetic modification in tissues of interest to address the temporal relationship between environmental exposures, epigenetic change, and psychiatric outcomes.
