by oral habits i mean like nail biting and thumbsucking

There is a lot more to ADHD (attention deficit and hyperactivity disorder) than just nail-biting. ADD or ADHD need to be diagnosed by a professional. but yes, there are some instances where oral habits can be an expression of someone with ADHD that's been placed in a stressful situation. (stressful meaning outside their comfort zone).

More common manifestations of oral habits are found in cases of mild Obsessive Compulsive Disorder (OCD).

AD-HD stands for

Attention Deficit Hyperactive Disorder

It basically means the the person would have a short attention span, mood swings, hyper , bad behavior.

Some people may have all of the symptoms and yet some may only have one or two.
I suggest the person go to a doctor.

@ bebotech bad behavior is not a symptom of ADHD