Well, there are also slower/faster acting insulins so that system is also more complex than that, but yeah you are generally right.
I like to think of it with an analogy like you have a very intricate 3D maze and have to get a tiny ball into a hole, but you can only ever move the maze in one direction, and it resets between tries. Something like SSRI just pushes everything one way in a big swipe, and sure it might just solve a particular puzzle, but there are endless others where such low-precision method has no way of succeeding. Of course that’s why psychotherapy is a must have for any sort of medication.
I like to think of it with an analogy like you have a very intricate 3D maze and have to get a tiny ball into a hole, but you can only ever move the maze in one direction, and it resets between tries. Something like SSRI just pushes everything one way in a big swipe, and sure it might just solve a particular puzzle, but there are endless others where such low-precision method has no way of succeeding. Of course that’s why psychotherapy is a must have for any sort of medication.