Oh, I was going from memory, so I guess that part's wrong.
But there are effective antidepressants that aren't strongly based on the serotonin effects SSRIs have, like trazodone (weakly increases it) and especially ketamine (doesn't do it, works better than most antidepressants, works near-instantly instead of taking weeks).
And I would like to add that ketamine has nothing to do with the monoamine hypothesis, it is an NMDA receptor antagonist. It has nothing to do with serotonin, dopamine, and noradrenalin.
See my other comment about the growing interest in the glutamate system instead of serotonin and the like.
But there are effective antidepressants that aren't strongly based on the serotonin effects SSRIs have, like trazodone (weakly increases it) and especially ketamine (doesn't do it, works better than most antidepressants, works near-instantly instead of taking weeks).