To be over-reductive: If you're at -3 due to symptoms, whichever treatment minimizes those symptoms like +3, but the given treatment(s) have short and/or long

To be over-reductive: If you're at -3 due to symptoms, whichever treatment minimizes those symptoms like +3, but the given treatment(s) have short and/or long term adverse effects that are -1, that's a net gain. But different people assign unnamed different constants with different magnitudes to different things.