My 18-month-old seems more easily distracted than his friends; he also hits more often. Could this be an early sign of ADD/ADHD?
Most 18- to 36-month-olds who act this way are simply showing their strong will and absence of reasoning. That said, children with attention-deficit issues often are tremendously active and aggressive. They also may have a strong aversion to being cuddled or read to; they may display delayed gross- or fine-motor skills (such as not crawling or having a good pincer grasp at about 9 to 10 months); and they may be clumsier and much more difficult to control than their peers.
If you are worried that your toddler is quite different from others his age, insist on a developmental evaluation. Nobody knows your child better than you do.