Although I've already commented on a similar theme on "Mad Girl", I think the idea is also applicable here. Particularly in the chorus and the bridge, "Swallow" prompts the idea of Emilie's experience in the asylum and with anti-depressants/mood stabilisers. Within this theory, the sea would represent Emilie's depressive phases and when Emilie sings that she "will swallow/ if it will help my sea level go down", it would mean that she will swallow the drugs if it will help her stop feeling so low. "I'll come back to haunt you if I drown" within this context would be Emilie's warning to those making her take the drugs that if they don't work and she still suffers from depressive episodes, she will "come back to haunt" them. When Emilie sings about "sinking slowly" this is maybe a refernece to her lifelong descent into her mental illness. Within the same part of the song, "Can I trust you?/But I don't want to" could refer to Emilie not wishing to follow the advice she's been given to take the drugs. In the bridge, the line "the brighter the light/the darker the shadow" perhaps refers to the idea that the stronger the manic episodes she feels, the stronger the depressive episodes. "I don't need a minder/I've made up my mind/Go away" could refer to Emilie's rejection of a doctor's medical care within the asylum.
There's lots more to write about but this has already been a long comment.
Although I've already commented on a similar theme on "Mad Girl", I think the idea is also applicable here. Particularly in the chorus and the bridge, "Swallow" prompts the idea of Emilie's experience in the asylum and with anti-depressants/mood stabilisers. Within this theory, the sea would represent Emilie's depressive phases and when Emilie sings that she "will swallow/ if it will help my sea level go down", it would mean that she will swallow the drugs if it will help her stop feeling so low. "I'll come back to haunt you if I drown" within this context would be Emilie's warning to those making her take the drugs that if they don't work and she still suffers from depressive episodes, she will "come back to haunt" them. When Emilie sings about "sinking slowly" this is maybe a refernece to her lifelong descent into her mental illness. Within the same part of the song, "Can I trust you?/But I don't want to" could refer to Emilie not wishing to follow the advice she's been given to take the drugs. In the bridge, the line "the brighter the light/the darker the shadow" perhaps refers to the idea that the stronger the manic episodes she feels, the stronger the depressive episodes. "I don't need a minder/I've made up my mind/Go away" could refer to Emilie's rejection of a doctor's medical care within the asylum. There's lots more to write about but this has already been a long comment.