Depression arises when the brain's mood-regulating networks, especially circuits involving the prefrontal cortex, amygdala, and hippocampus, stop communicating in a balanced way. Neurotransmitters like serotonin, norepinephrine, and dopamine fall out of their usual rhythm, which dampens motivation, pleasure, and energy.
According to the National Institute of Mental Health, depression is one of the most common mental health conditions in the United States, affecting an estimated 21 million adults each year. It is driven by a mix of genetics, brain chemistry, life stress, and overall medical health.
When these systems stay dysregulated for weeks or months, the brain can get stuck in a depressed state. That is why early treatment matters, and why patients who do not respond to a first or second antidepressant often benefit from adding primary care-based medication management plus non-medication options like TMS.
