Attachment disorder covers a wide spectrum and comes in more than one flavor. RAD is rare, but milder forms of attachment disorder are not uncommon. I have a RAD niece, adopted from a neglect situation, and it is truly a horrible disorder; if your DGS were RAD I suspect you would see the signs yourself.
My gifted son, adopted at 7 months, had the anxious/avoidant style of attachment disorder that made him quite a challenge to parent as a toddler, but he did slowly respond to attachment parenting. Now age 9, I consider him securely attached though I suspect that there are lingering issues that never entirely go away. He is also in my opinion ADD, though I have not pursued a formal diagnosis for this because I do not believe it would be helpful at this time. (I am diagnosed ADD myself.) I would not be surprised if the AD and the ADD were related somehow, but I do not consider it important to clearly distinguish one from the other. His needs are his needs, regardless of category.
I used to be sure he had an auditory processing disorder. But nope - he passed. There's a lot of overlap in a lot of this stuff.
