While kids will always experiment with new things and push the boundaries, and parents naturally worry that this will extend to smoking and even worse, drug taking. It's not as uncommon as you might think, with around a third of high school kids using marijuana at least once each year, and this includes children with learning disabilities. As a parent, it can be difficult to keep track of your child's activities and types of friends. Many parents often wonder if their child is participating in illegal activity, such as abusing drugs, and they may feel helpless because they do not know how to tell if their child is using. However, there are warning signs parents should be on the lookout for to determine if there's a need for drug rehabilitation before the problem progresses.