For a long time, the main story about mental illness—like depression and anxiety—has been that there's a "chemical imbalance" in the brain. This idea, which is usually explained in simple terms, says that mood disorders come from problems with neurotransmitters like serotonin, dopamine, and norepinephrine. According to this idea, mental illnesses are like diabetes or high blood pressure: a glitch in brain chemistry that needs a pharmaceutical fix, usually in the form of antidepressants or other psychiatric meds. This model has been useful in some ways, especially in reducing stigma by promoting the idea that mental illness is a medical condition rather than a moral failing. However, it is also deeply flawed and is increasingly recognized as scientifically outdated.