Schizophrenia isn’t only about hallucinations. For many people, the hardest day-to-day challenges are cognition and function : attention, working memory, processing speed, motivation, and social connection. Over the last couple of decades, one scientific finding has stood out for how consistently it appears: Many people with schizophrenia show reduced ability to “sync” brain activity to a fast rhythm—especially around 40 hertz (40-Hz). What is the 40-Hz test? Researchers ofte