what’s the difference between SSRIs, NDRIs, and SNRIs (in treatment and basic chemistry)

Question

is there any simple way to explain how these work differently and treat things differently, like why would someone choose one of the three over the other at a given time (if they almost all treat the same thing, just act differently), does it come down to something super nitty gritty maybe?

In: Chemistry

Answer 1

In the simplest terms, they all are antidepressants in a sense, but they target different chemicals in the brain, and that in turn affects how they work and who they help. They all work on the basis of slowing down the reabsorption of a specific chemical, leaving more of it in your chemical ‘reservoir’ so it can be used by the brain.

SSRIs are Selective Serotonin Reuptake Inhibitors. They focus more on serotonin, serotonin is the chemical that helps your mood, happiness, and anxiety. They block the reabsorption of serotonin, leaving more of it available to be used by the brain. With things like Depression, anxiety, and OCD, the brain either doesn’t produce enough serotonin or absorbs too much of it, SSRIs block this from happening.

SNRI’s are Serotonin-Norepinephrine Reuptake Inhibitors. These target Serotonin AND norepinephrine, which is related more towards energy and alertness. This is good for depression, anxiety, or mood altogether because sometimes these emotions bring with them a very dull energy that makes you tired all the time. SNRI’s block Serotonin and Norepinephrine reabsorption, leaving more of BOTH chemicals in your brain.

NDRIs are Norepinephrine-Dopamine Reuptake Inhibitors. These are more focused on just norepinephrine and dopamine, which like the previous one with the Norepinephrine, involve energy, but with the dopamine it helps it a step further with the motivation+reward part of the brain. NDRIs are good for someone with very low motivation, or if they are trying to avoid certain SSRI side effects.

TLDR:

SSRIs are good for mood and anxiety. They let more of your serotonin build up.

SNRIs are good for low energy. They let more of your serotonin *and* norepinephrine build up.

NDRIs are good for low motivation or focus. They let more norepinephrine *and* dopamine build up.

But, this is why you normally talk with a psychiatrist and they can weigh each one compared to your specific symptoms, and if certain side effects outweigh other side effects. Sometimes it’s just a trial and error process, the brain is complicated and getting these chemicals to the right place can take some time.