Can social anxiety disorder be caused by underlying add?

ADHD and Anxiety: Anxious behaviors may be caused by ADHD, as one of the key issues with ADHD is a problem with "executive function", essentially a problem with seeing the big picture and planning ahead appropriately. Likewise, anxiety disorders are often misdiagnosed as ADHD, as individuals may act impulsively in situations that are perceived as threatening or uncomfortable.

Social anxiety &ADHD: Good question. The way this works for people can be that the challenges of managing a lot of information is overwhelming their processing leading to fear of failure. This gets generalized out into the world, fear of social failure. Social processing can be very complex. Feelings of inferiority, like people will find out that you are really inept or whatever is common. Find ADHD specialist!