Your son's "disrespectful" behavior is not, in and of itself, reason to suspect ADHD. Impulsivity, non-compliance and social inappropriateness are just some of the behaviors attributed to ADHD.

The American Psychiatric Association and the American Academy of Pediatrics are excellent resources to help familiarize you with the diagnostic criteria for ADHD, as well as other childhood disorders. Mood disorders, such as depression and anxiety, can lead to "acting out" behavior, as well as undiagnosed learning disabilities. Knowing more about these issues can help you decide when to consider having your child tested.

Changes in family life can also cause acting out in school. Examine if there have been any recent developments in the family or the family routine that might be cause for anxiety. Remember, what may not be upsetting to you may be to your son.

Try some investigative reporting with your child. Be careful not to blame either the teacher or your child. Try something like, "Gee, you had such a good time in kindergarten, I wonder what's different about first grade." Give your child an opportunity to express what is difficult about his experience so that you can strategize some solutions.

Make sure you are clear on what behavioral expectations the teacher has of your child and that your child is clear about them as well. Be specific and break the classroom rules down into manageable steps.

Over the course of your child's life he will need to learn how to deal with people he may not care for. One thing you can do at home is avoid "venting" about people in authority, like a boss, spouse, etc. It is best to model "working it out" rather than "acting out."