All antipsychotics are sedative so i'm not surprised in improved your sleep. Abilify mechanism might be a little confusing to those not in the medical world. It's the most mild of the anti-dopamine drugs, but it's overall effect is to lower dopamine. It works as a partial agonist. So it blocks your normal dopamine molecule and replaces it with a less potent partial "dopamine". So essentially, you're dopamine receptors are just getting stimulated less than they normally would be. ​ There have been isolated case reports of people on abilify actually developing a stutter afterwards. The dopamine system is a bit more complicated than people make it to be, so there are probably other mechanisms going on. Put in terms of potency, abilify is usually the least strong of all anti-psychotics and generally just thrown into a cocktail for a patient with lots of other issues.