Our minds affect the environment around us. Different states of mind affect reality differently. Perhaps this is why substances which have different effects on our minds are illicit in a world which demands constant control over our environment:
We are products of circumstance but circumstance seems oft to be a product of us. Most of what happens, we allow on some level. As much as we like to play the victim, we must acknowledge that we, for the most part, are in control of our mental state. A vortex of negativity polarizes and magnetically attracts more negativity. Once we chose to be accepting and positive, we attract more of the same... in theory.