Serotonin and the Brain: Why Antidepressants Take Weeks to Work

Understanding the Brain · Oct 19, 2026 · 4m · transcript

Serotonin plays an important role in mood regulation, emotional processing, sleep, and communication between neurons, but its relationship with depression is far more complicated than a simple chemical imbalance. In this episode of Understanding the Brain, we explore how serotonin signaling works, why antidepressants can alter neurotransmitter activity within hours yet take weeks to produce clinical improvement, and how the brain adapts through changes in receptor sensitivity and neural plasticity. We also examine what happens when serotonin activity becomes dangerously excessive, including…