I'm going to throw this one out here:
I don't believe the NBA has the steroids problems that MLB and the NFL do. I don't believe there's a drug that will help anyone gain speed, hit more shots, make better passes, rebound more effectively, block more shots, or get more steals.
That's not to say there's not steroid use. I believe it's there, but the stories are more typical of Don McLean - steroid use in the aid of healing of injuries. Now that, I believe, is much more common - most notably among the chronically or frequently injured, and espeically around the league's marginal players. So, yes, because they're available to the court whereas without steroids they wouldn't be, steroids increase numbers, but I'm convinced that that's the ONLY way.
I simply believe basketball players gain so radically less from steroids that their use simply isn't worth the bang-for-the-buck, unless you're an often-injured fringe player. For the rest of the guys, they don't make much sense.