I have read in many and varied sources that "
schoolboy" is street-talk for codeine. Now, somewhere or sometime perhaps it is or was, but not ONCE, as in never, during my reasonably extensive research regarding various street scenes did I ever hear it used. T3s, T4s, codeine...yeah, those one might hear...but
schoolboy? Me not think so, unless it is just
something pre-1960s and fell out of use.