Second, the “environment” is to some extent unbounded in a way the genome is not. Both children and adults are exposed to a range of experiences across the multiple social and physical contexts in which they are embedded (e.g., families, school, neighborhoods, workplaces); all of these experiences and exposures can contribute to health.141 Focusing on well-defined measures of environment where there has been robust and consistent evidence to support a relationship between the exposure and depression is one way to start. Such a list of measures could include in utero exposures (e.g., viruses, toxins, alcohol and drugs), social deprivation (e.g., poverty, child maltreatment), and enrichment (e.g., psychosocial interventions and treatments). However, even if we select the same environment, such as child maltreatment, there are still multiple different types of maltreatment, multiple ages to consider when the maltreatment occurred, and multiple ways to measure maltreatment (e.g., self report, administrative records, clinical interview).
