That is one alternative hypothesis. The reality may be even more complex than that. We don't really understand these brain systems and of course they're all tangled up in feedback loops with each other.
I do wonder though if it does make you numb if that isn't always bad. For some people depression might be related to an excess of sensitivity or some past trauma. Numbing that a bit might help them move past it and might be beneficial to their healing. Of course this might not be the case for people whose depression has some other source and it might not be the case for continuing treatment. It's possible that some people might benefit from taking certain drugs for a period of time but not forever.
It's all quite complex, individual, and not yet anywhere close to fully understood.
I think numbing might be useful if, for example, you’re currently incapable or illequiped to deal with whatever underlying thing is causing it, but its not a soltuion by itself, but rather a delaying tactic until the point when you can deal with or treat the issues.
I do wonder though if it does make you numb if that isn't always bad. For some people depression might be related to an excess of sensitivity or some past trauma. Numbing that a bit might help them move past it and might be beneficial to their healing. Of course this might not be the case for people whose depression has some other source and it might not be the case for continuing treatment. It's possible that some people might benefit from taking certain drugs for a period of time but not forever.
It's all quite complex, individual, and not yet anywhere close to fully understood.