I agree, amphetamine/methamphetamine really boost my creativity and productivity, however it was too much for me to handle. I have experienced some of the most intense mental breakthroughs and produced some of my most creative works with speed, but it takes it's toll in a heavy way, atleast if you go at it like I did. I am just now starting to feel normal again 6-months later after recovering from a 3-month speed fueled intellectual adventure that landed me in the mental hospital twice due to psychosis. I think there is a reason our minds are calibrated with particular dopamine and neurotransmitter levels, when we alter these levels we see the amazing potential of the human mind, but the brain hardware can't handle it unfortunately. Addiction is hard, now I am back to coding (sober) and I find myself thinking about having a bump whenever I feel unmotivated, which is often.