Lilianne is beginning to develop a fear of strangers and will reach for her mother when she sees someone who is unfamiliar. it is likely that lilianne has also just

It is likely that Lilianne has also just developed a sense of object permanence.
Object permanence refers to the fact that infants know that certain objects/people exist even though they cannot see them at the time. In the beginning, infants might be scared of meeting new people because they still don't fit their existing schemas (they are still unfamiliar with them), but once they get acquainted with that person/object, they will no longer be scared of them, which will happen to Lilianne as well. 

40 percent and 10 percent

According to sources, the most probable answer to this query is that this type of neurodevelopmental disorder is more observed in children that in adults. Typically, adults would be diagnosed with an anxiety disorder called general anxiety disorder when ADHD progresses into adulthood. Thank you for your question. Please don't hesitate to ask in your queries.