Is adderall(adderrall) addicting?

My 5 year old son takes 20mg.tbs of adderall (adderrall) 3 times a day, 7am,12noon,and 5pm.We are talking about increasing his mgs.When we moved him from 10mgs.,to 20mgs,I could see a differance in him.Now, he is back to his old ways.Can he get immuned to this medication?He is starting with "I'm scared"when it's time to go to bed.Is he getting to much medication?His appetite is good so, i'm not worried about that.I want to now if ADHD, is a disability or is it a disorder that we have to work with.I am curious if alot of his behavior is a behavior problem or if it's the ADHD.I want to go to work but, there is no one I can leave him with that I can trust to understand ADHD.I feel that noone can handle him the way I can.If someone can just answer the few questions I have asked, it would be GREATLY appericated..

[HFHS MD - RG]

To diagnose ADHD, the patient for at least 6 months has had symptoms of that is maladaptive and inconsistent with his develpmental level
[a]inattention (eg. difficulty sustaining attention, often does not listen when spoken to, etc)
[b]hyperactivity(eg. fidgetines, is often "on the go" etc.)
[c]impulsivity (eg. often has difficulty awaitin ghis turn, blurts out answers before question have been completed

No one really knows the reason why a medication that used to work seem to lose its efficacy in time.

At this age, it is fairly common for them to be afraid to go to bed because of "the dark or the monsters".

Although Adderall (adderrall) is a controlled substance because of its potential for abuse in the streets, studies show that it does not cause addiction to children who uses it to treat ADHD.