Boston Children’s Hospital Answers profiles the research of clinician-scientists Tamar Katz and Kinga Tomczak, studying potential differences in the microbiomes of individuals with these disorders. If they identify imbalances, their hope is that correcting them may prevent or lessen symptoms. On a separate but related front, they are collaborating with neurobiologist Takao Hensch, who is exploring brain circuits involved in OCD in a mouse model and whose research on critical periods in development may provide insights into the best timing for any potential interventions, including ones affecting the microbiome.