Everybody knows Soulja Boy - the dance/rap phenom thats known for his most famous "Superman" dance and jingle.
Most people know what Promethazine-Codeine is too. That "purp" or "sizzurp" made most popular by celebrity rappers. (Lil' Wayne & Future to name a few.)
In VICELAND's most recent episode of Black Market, Soulja Boy speaks on his lean addiction in terms of assisting his creative output for his music.
Though it may help his workflow, Promethazine-Codeine has been deemed "deadly" if over consumed. Side effects are those similar to Heroin (seeing as though it's an opiate) causing withdrawal symptoms leading to sporadic seizures.
Read more about the "Promethazine-Codeine" here.