I may be below the status quo with regard to material possesions, however, i believe this is incredibly subjective as many of us know that with the right heart, an impoverished person may find true happiness and a wealthy person may be living in hell. Nonetheless, for the sake of loved ones who suffer proxy-consequences for my past behaviour, I'm not where I wish I could be.
How successful? I feel I have made great personal strides while using that lead me to believe that my "self"- the sum of my behaviour, thoughts and beliefs has grown tremendously. Whatever emotional or neurological challenges I'm faced with, using puts me in a place where I feel "normal"; "normal" as compared to however "mainstream/average" individuals are defined. I've also observed that some of my friends, acquaintances, colleagues (i.e., doctors, therapists, accountants, corner-store clerks) have some of the same issues I do or issues in general. Within three years, I've lived in three countries that differ like night and day and I observed that people- their desires, dislikes and general behaviour is the same everywhere; only the culture is different.
But successful? My actions may be considered "self-medicating" with copious amounts of opiates and kush, but I feel I have found peace and a peace that allows me to grow and a feeling of "wholeness" which enables me to reach out and help others. So with regard to success, I may not have a penthouse suite, but I feel complete, stable and able to love others. Love. Most of us think we understand love, but in addition to it's pleasures, love will require sacrifice, pain and reluctant honestly (e.g., when I've fucked up). So by my definition of love and wholeness, if I put others first and it doesn't interfere with my responsibilities, I believe that would qualify as "success".