The steroid psychosis that jeff is talking about is the kind of steroid psychosis one gets from taking high doses of say, Prednisone, orally.
The small dose that is given to you in your asthma inhaler does not enter your bloodstream except in the tiniest fashion. This is like asking if your cortisone cream you're putting on a rash would cause steroid psychosis. The answer is likely no.
Poor asthma control, theophylline, or any stimulant inhalers such as albuterol/ventolin, Xopenex, Advair, Serevent or Oxeze/Foradil or Symbicort could very easily cause insomnia. This is usually temporary.
If insomnia persists for a long period of time (more than a few weeks,) or is severe (to the point where you get no sleep whatsoever,) please go see your doctor and have the cause of your insomnia investigated, since it's very likely something else might be causing it.