Maybe I can answer a little bit of this.
I would say that fetal alcohol spectrum disorder is much broader than a mental health disorder, because it impacts communication and all of those other brain functions. It is often comorbid with an anxiety diagnosis or a diagnosed depression or disruptive mood disorder, but FASD is much bigger than anxiety itself. If you have just anxiety, albeit a significant disability, and all of your other brain functions are intact, you are very different from somebody who has FASD and who has significant impairment across many areas.