Two recent studies add to the mounting evidence that environmental toxins deserve a place in the bio-psycho-social-spiritual model. The first study correlated ADHD symptoms with exposure to endocrine-disrupting chemicals found in plastics, pesticides, and processed food. Based on urine samples collected from 205 adolescents, they found a strong correlation between levels of these chemicals and ADHD symptoms as rated by parents, teachers, and teens. The correlation does not prove causation, although it did hold up after adjusting for cofounders and is supported by earlier research in adults. These are the same chemicals that are linked to early puberty and cancer, and they are among the reasons we’re advised to avoid microwaving in plastic (Shoaff JR et al, JAMA Netw Open 2020;3(8):e2015041).

The second study was a meta-analysis of ultra-processed food consumption from 23 cross-sectional and prospective cohort studies. Rates of depression were 20%–30% higher in people whose diet was packed with ultra-processed foods, and rates of metabolic syndrome were about double. Again, while causation is only implied here and not proven, there are many plausible pathways by which processed foods might impair brain function (Pagliai G et al, Br J Nutr 2020 Aug 14;1–11).

Ultra-processed foods include the usual suspects—packaged snacks, sodas, and fast and frozen foods—as well as deli meats, condiments, and mass-produced breads. Learn more in our 60 Second Psych Carlat podcasts from 10/31/20, 11/4/20, and 11/7/20.