Veling et al. (3) have been able to address this issue in a thought-provoking study. They examined age at migration and risk of psychosis. This is an area where terminology can be confusing. First-generation migrants are born in one country and move to another country; these individuals can arrive as newborn babies, children, teenagers, or adults. Second-generation migrants are those whose parents were born abroad and who themselves were born in the new country. The act of migration is a stressful process, and for some, the stress is amplified by belonging to an ostracized and easily identified minority group. By examining age at migration in first-generation migrants only, the authors were able to explore whether there was a critical window for exposure to the yet-to-be-identified risk moderating variable. If psychosocial mechanisms related to racism and marginalization only operated during adulthood, one would predict that migrants who arrive as babies and those who arrive as teenagers would be exposed to the same “dose” of psychosocial stress (i.e., throughout adulthood, assuming they do not return, once migrated, to their country of origin). Indeed, those who arrive as young adults might be prone to the greatest social dislocation and stress due to lack of language skills. However, Veling et al. found that migrants who arrive as babies or toddlers had the highest risk of schizophrenia, with the risk decreasing with age at migration thereafter, such that those who migrated at age 29 years or older had no greater risk of psychotic disorder than the nonmigrant population. They conclude that the critical window of exposure is during early life.