Andrew Huberman· PhD
So what is an SSRI? An SSRI is a drug that prevents the re-uptake of serotonin at the synapse. What are synapses? They're the little spaces between neurons where neurons communicate with one another by vomiting little bits of chemical into the space, the synapse, and then those chemicals either evoke or suppress the electrical activity of the next neuron across the synapse. And in this case, the neurotransmitter, the chemical that we're referring to is serotonin. SSRI, selective serotonin reuptake inhibitors prevent the reuptake of the chemical that's left, in this case, the serotonin that's left in the synapse. After that, I call it vomiting to be dramatic, but it's not actually vomiting, the extrusion of the chemical into the synapse. And as a consequence, there's more serotonin around to have more of an effect over time, the net effect being more serotonergic transmission, more serotonin overall. So not more serotonin being made, more serotonin being available for use, that's what an SSRI does.