What's the difference between running out of a UBI stipend, and running out of a paycheck too early? Either way, that addict is in trouble. At least UBI won't put them on the street when their addiction renders them useless for work.

IMO, long cycles in pay (weeks or a month) are suboptimal. If the money streamed in continuously, slowly, then it would only "run out" for a matter of minutes, although it would still take a while for a useful amount of it to re-accumulate.

Opiate addiction is an important, yet unrelated problem. With regards to UBI, its no different than a million other addictions (gambling, alcohol, social media, etc)... We, as a society should look at reasonable ways to address addiction issues of all sorts, coupling that solution with UBI implementation doesn't seem like a great idea.