ADHD - is it a womb twin survivor thing?

I found a nice slide show that simply describes ADHD  (Attention deficit hyperactivity disorder)  in adults.

(View it here) 

ADHD: It's Not Just for Children

Most people think of children when they hear the term attention deficit hyperactivity disorder. But 30%-70% of kids with ADHD continue having symptoms when they grow up. People with ADHD have an imbalance of neurotransmitter activity in areas of the brain that control attention. In adults, the inability to stay focused can derail careers, ambitions, and relationships. Many adults don't realize they have the disorder, leaving them mystified about why their goals always seem to slip out of reach.

 

ADHD really came to the attention of the media in the 1980s, when it was first linked to food intolerance. At that time it was thought (oh no, not again!) that these restless children who could not concentrate were the products of "poor parental upbringing."  The parents in question made sure the world knew that it was the children, not the parents, who were driving this.
But the symptoms persist into adulthood, far beyond the reach of parents.  For ADHD adults,  the symptoms are now simply regarded as to do with a "lack of self control".   But no one knows why this is. What is ADHD, anyway?