I do NOT think this is about drugs at all. I think that it is a bit about paranoia, but not completely. He is afraid of something, but I think that the paranoia is of himself (I'm being followed/I look around/Its only my shadow creeping on the ground). I think something happened and the memories are driving him crazy. I think the "demons in his head" refer to personal demons, therefore memories. He's been hurt, and he's afraid of himself.
I do NOT think this is about drugs at all. I think that it is a bit about paranoia, but not completely. He is afraid of something, but I think that the paranoia is of himself (I'm being followed/I look around/Its only my shadow creeping on the ground). I think something happened and the memories are driving him crazy. I think the "demons in his head" refer to personal demons, therefore memories. He's been hurt, and he's afraid of himself.