I think it is possible that any chronic medical condition, whether it be diabetes, cystic fibrosis (as examples) or CAH can cause depression and counselling is usually available (perhaps you should discuss the possibility of this with your consultant?) However another possible contribution to depression in CAH is the actual steroid you take (glucocorticoid) .  I have heard in particular that prednisolone (which suits many and they don’t have problems) can cause suicidal tendencies in others.   Talk to your doctor about how you are feeling and hopefully he will be prepared to help.  I am sure others on this board will have advice too - you are not alone!