Well, from this description of the study, it's hard to tell. It seems that kids who report a more positive attitude toward drug use are correlated with having heard from their parents about their own past drug use.
But how that translates into actual increased drug usage, or drug problems, is still unestablished, nor is the correlation necessarily causation.
I think, within certain bounds, honesty with kids is better in the long run than dishonesty. That doesn't mean spill your guts about everything (which would be simply inappropriate), but hiding stuff, even in such broad brushes as past drug or alcohol use, may keep "ideas" out of your kids' heads, but will not in the long run promote the much more important quality of trust.
Reshared post from +Andrew Eva
Ok, so maybe telling your kids about that crazy time you were high and jumped into a swimming pool off a 4 story building wasn't such a great idea.
This article was the best description I found of the study, which is kind of embarrassing as it is still devoid of specific information.
When it comes down to it from a personal perspective, I think it has the most to do with what your kid will be receptive to, as opposed to their being a best method to broach the conversation.
Hey Parents, Don’t Tell Your Kids You Did Drugs
Teens whose parents discuss their past drug use with them are likelier to have more positive views of drugs

I agree with the focus on trust.
Are we looking for the next generation of kids to reject drugs so thoroughly that we reinforce the hidebound mentality that created our modern drug-war casualties (nearly 1% of our citizens)? Are we instead hoping them to embrace every novel chemistry with total disregard to consequence?
The answer is neither. Instead, we want our kids to be sensible and informed. We want them to be cautious but not paralyzed with fear. We want to know that they will not dismiss people just because they are drug users or friends with drug users. But we also want to know that, if they ever do decide to experiment, that they will do so as safely as possible: with people they can trust, in an environment where they can get help. The last thing we want is sheltered kids breaking under peer pressure and drying some random substance in the basement, club, or party of someone they barely know.
We want them to use caution, have self-control, and be willing to call their parents when they need help. And to do that, we need them to trust us (and, also, to understand that we do trust them as well, and that we will accept mistakes). We can't do this by refusing to talk about those things which will strain trust the most.
Yes. That. Exactly, +Gary Roth.
And I imagine the issue (and your comment) can also be said about sex, too.
+Dave Hill While I didn't say so explicitly, yes. And if you can build trust enough to overcome these two issues, you can build trust overcome almost anything.
Well, that's certainly my wife's and my intent with our daughter … (looks about for wood to knock on).