Yes, psychiatric medication extremely reduces my motivation and ability to create. Never touched street drugs and I haven't noticed if alcohol increases creativity. I have considered ditching my medication on account I hate this fog (affects mental clarity as well as ability to make art). But I realise what a mess my life would be. When it does come to art I must force myself to do so as though I were undertaking an exercise. I am never happy with the finished products. They always seem to me to be lacking something.