Game Mechanics Help: Question about stat reductions

I've been trying to make a pokemon game of my own but I can't figure out anywhere about the stat reductions. What I mean by stat reductions are attacks like Growl, which lowers your oppenents Attack stat. Now I know that when you use it, you openents Stat Reduction point(or whatever you call it) lower by 1 and it last for 1 turn. If you use one one of those moves more then once, does the turns and state add up? Or do they just cancel the first one?

They add up each time you use it. The stat drop doesnt last just 1 turn, it lasts until you switch out/faint.
Hope I helped!

Thanks for the help. I think I understand it now, everything will be running better now. Be sure to look for my game in less then a month!