Why is methamphetamine so addictive?

For the life of me I can't describe how addiction to meth has affected my life and the lives of many around me. Even though I have been clean for 609 days now, I still struggle with the insanity of it all. I want to devote the rest of my days to helping meth addicts find a better way of life...

: http://alcoholdrugstreatment.info/why-is-methamphetamine-so-addictive