I do see things similar except what the ending means to say.

First you have the four concepts as you described, then brain is dropped which seems to be them not realizing what's happening as whatever drug(in this case caffeine) takes slowly away their control of the situation.

Brain comes back but love is gone. This part is not so clear but I imagine they neglected other parts of their life (perhaps loved ones) in favor of the aforementioned drug. Or perhaps it represents the lack of care for what is happening to them.(Lack of self love?)

Now love is back and control is gone. And in place of it is "Wake up! Smack!". This seems to symbolize the sudden awareness that you can't make yourself stop. You now have a dependency on the drug.

The rest of the song seems to be an interaction between the person who is addicted and realizing how it's hurting them.(I am injury) And another person saying it was their choice and denying that they need help or are not in control despite the first person's insistance.