Hi – wise words lurknessmonster – thanks. Reading itself isn’t an issue but concentrating on what I read certainly is. I guess it’s all too complicated as you say. I think you made a good point about the subtle effects things like tyrosine might have. I don’t need subtle effects, I need something that’s going to explode in my brain and shake me into focusing, concentrating and not procrastinating any more. Subtle won’t do it. 
