In a study by Rosenblum, et al. (2008), children with ADHD had poorer handwriting than non-ADHD children.   Additionally, when children with ADHD were off of their medication, they took an even longer time to copy a paragraph as compared to when they were on medication.

Many parents will not be surprised at these study results.
(That was my comment, not the study’s comment.) 🙂

Rosenblum, S., Epsztein, L., & Josman, N. (2008).  Handwriting Performance of Children with Attention Deficit Hyperactive Disorders: A Pilot Study.  Physical and Occupational Therapy in Pediatrics 28(3), 219-234.