CarolHi Adina,
I know that there are a lot of ideas and terms being thrown around, and it's easy to get confused. Re. what you said about Jake's circadian rhythm being possibly being out of whack: Circadian rhythm is something that is innate, kind of like day and night. The issue with dosing is really whether or not you work with a body's natural circadian rhythm or you work against it. Either way, you should be able to achieve adrenal suppression, but the point is that if you work with natural circadian rhythm, you'll probably be able to do it with a lower dose of medication, and, therefore, fewer side effects. Since one of the main concerns with a CAH child is a normal growth rate---and high doses of glucocorticoids have the effect of stunting growth---it is desirable to minimize the amount of medication that one needs to take, in order to achieve this.
I'll borrow Val's thermostat analogy: Imagine that you want to keep a house at a constant temperature of 68 degrees in the wintertime. What times of the day would you turn up the heat, and what times of the day would you turn it down, in order to use up the least amount of fuel?
I think most people would agree that it would be most energy efficient if you turned up the heat, at night, when it's cold; and down, during the daytime, when it's warm. If you did it the other way around, it would not be impossible to keep the house at that constant 68 degrees, but it would be much more difficult, and you'll probably waste a lot more fuel in the process, because you're working against the natural heat from the sun.
In a way, it's really not much different with dosing and circadian rhythm. The idea is to give higher doses of meds when you need them, and lower doses, when there is less need. Since ACTH levels are naturally highest in the morning hours, working with natural circadian rhythm would indicate that it is most efficient to give the highest doses of replacement cortisol in the mornings, as well. In a way, that's really all there is to it. Simple, right? LOL!