What prompts neurological disorders in children is “very complex,” notes Frederica Perera. Adding to the challenge of disentangling the various contributing factors is that while research on—and regulation of—chemicals typically looks at one substance at a time, people are exposed to multiple chemicals concurrently. Further adding to this complexity when it comes to brain development are social stresses that “act on the same part of the brain region,” explains University of Rochester professor of environmental medicine Deborah Cory-Slechta. She and others are finding increasing evidence that nonchemical stressors such as maternal, domestic and community distress can prompt adverse effects on early brain development, either on their own or in combination with neurotoxic chemicals.
Birnbaum says this apparent interaction between chemicals and nonchemical stressors is “very concerning and very important.”