Attachment disorder isn’t on the autism spectrum, although it can present with some overlapping characteristics at times. But RAD (reactive attachment disorder) kids usually develop normally. Unless there are other contributing factors like fetal alcohol syndrome or something.
When you first meet a person with RAD, you might come away thinking what a smart, engaging child. They are extremely superficially charming, can carry on intelligent conversations and come across as well adjusted individuals. But the whole time, they’re sizing you up to see how they can manipulate, control, and ultimately hurt you.
There’s an old documentary called Child of Rage that follows the case of a child, Beth. It’s kind of graphic, but it gives you a good idea of what’s going on. I’ve seen kids that are worse than her. My adopted daughter was hiding kitchen knives under her pillow. When I found them and asked her what she was planning to do with them, she said “stab you while you’re sleeping.” She knew it was wrong, but she didn’t care.