An article at the Sleep Disorders Guide lists sleep myths. Myth #8 states that shows the correlation between ADHD-like behavior and insomnia.
"Myth 8: Children who don't get enough sleep at night will show signs of sleepiness during the day.
Unlike adults, children who dont get enough sleep at night typically become more active than normal during the day. They also show difficulty paying attention and behaving properly. Consequently, they may be misdiagnosed as having attention-deficit hyperactivity."
This is yet another important consideration when told your child may have ADHD. Look at all possible environmental factors which may be contributing to their behavior before loading them up with medication. Other factors to consider are; caffeine intake, trauma, speech/hearing/seeing problems, problems in the home like domestic violence or substance abuse, allergy medications (especially inhalers) or physical/sexual/emotional abuse in the home.
You can see the original article at Top 10 Sleep Myths.