Depression is far more complex than a simple serotonin deficiency. Modern psychiatric research, including evidence summarized by the National Institute of Mental Health, points to multiple overlapping biological systems: neurotransmitter networks, inflammation, brain circuit activity, and genetics. When one or more of these systems do not respond to traditional medications, depression can become persistent and resistant.
Glutamate and dopamine signaling, in addition to serotonin, play important roles in mood regulation. Many traditional antidepressants act primarily on serotonin, which means patients whose depression is driven by other neurotransmitter systems may see limited improvement. Inflammatory cytokines and stress-related hormonal changes can also blunt the effectiveness of standard medications.
Brain network dysfunction, particularly in the dorsolateral prefrontal cortex and connected mood circuits, is another mechanism. This is precisely the area targeted by TMS therapy with ExoMind, which uses focused magnetic pulses to restore healthier activity patterns when oral medications alone are not enough.
