How Do Antipressants Work?

Prozac makes your brain grow. What happens in the brain and body when you take an antidepressant?

By Hara Estroff Marano, published on January 3, 2003 - last reviewed on November 20, 2015

Forget what you think you know. It has nothing to do with serotonin
or other neurotransmitters. OK, it has something to do with them, but
that's not the key.

Evidence now indicates that all effective depression treatments
turn on genes that produce nerve growth factor in brain cells. The nerve
growth factor literally makes your brain grow; nerve cells sprout new
branches, connections between neurons flourish, you learn and adapt more
easily, regaining behavioral flexibility.

Antidepressants kick off a transient increase in neurotransmitter,
which functions as an external messenger between one nerve cell and the
next one down the line. The neurotransmitters important in depression are
serotonin, norepinephrine and dopamine. They get taken up on the
receiving cell by a receptor that sits on the fat-rich surface of the
cell and is coupled to a protein inside the cell. The protein then
activates a cascade of signals inside the cell resulting in an increase
in the specific growth factor called BDNF, brain-derived neurotrophic

Interestingly, the treatment that produces the largest increase in
BDNF isn't a drug at all. It's electroshock therapy.