Chems, Comedown and Addiction
Most chems have a risk of addiction and a nasty comedown after the effects wear off. Everytime the effect wears off, the character has to roll EN vs. the Addiction difficulty. If it fails the character becomes addicted and suffers the comedown permanently until the addiction can be healed. Healing needs a successful Medicine check vs. the Addiction difficulty +1. Consuming the chem removes the effects of the comedown temporarily.