SSRIs can initially increase serotonin in synapses, leading to temporary mood and energy improvements, but the nervous system may adjust, causing them to stop working long-term and potentially leading to side effects like weight gain and slowed metabolism.

“so is serotonin like so are so is so are ssris maybe and when I say maybe what I mean by that is if you really have a metabolic problem like say something's wrong with your mitochondria or you're recovering from an illness and you know that or or there's just some metabolic problem in your body that metabolic problem is real if you start to feel unpleasant you will I mean feel unpleasant it will feel your mood will be negative if you start taking serot if you start taking ssris which will leave more serotonin in the synapses of your uh neurons before it's re it's taken up again that will juice the system you will be able to spend you'll be able to move you'll feel like you have more energy for a while but your nervous system is is a complex system and so it's going to make adjustments elsewhere to try to deal with that budgeting problem so exactly what happens when you take drugs of abuse and what happens on the short term can happen for some people with ssris on the longer term where at first it starts to work and then it stops stops working and you start to gain weight and you know and your because your metabolism is slowing because your brain is attempting to deal with that with that budgeting problem”