"Anti-Depressants: How They Work" Dr. Fieve: "Anti-depressants tend to work in a technical way with the brain. The serotonin re-uptake inhibitor blocks the uptake of serotonin in the brain cell, and by doing that the brain fiber is allowed to continue shooting, whereas before it was blocked. The same is the mechanism that is used for the tricyclic antidepressant, the dopamine uptake inhibitor, so each of these antidepressants have a technical, mechanism of action. There's a theory of how they act on the brain cells, and how that in turn restores normalcy. Now this is a theory, may be totally wrong, may be 10 other theories why a drug works; all these drugs have theoretical backgrounds of why they work, but no one knows for sure."