Yes, a person (child or adult) can have both narcolepsy and ADHD. While these conditions can be independently present at the same time (i.e. one is not causing the other), it is often the case that the narcolepsy ends up creating the symptoms of ADHD. This is primarily because the poor sleep regulation and excessive sleepiness associated with narcolepsy can make it difficult to concentrate. They can also lead to various degrees of depression, which in turn can make concentration difficult. If your child has been diagnosed with narcolepsy, and you are concerned he/she may have ADHD also, you should have him/her evaluated for learning issues by a child psychiatrist. Alternatively, if your child has been diagnosed with ADHD and you now suspect narcolepsy, it would be best to have him/her evaluated by a sleep specialist. These people are equipped to administer either a sleep latency test or polysomnogram test to diagnose even mild cases of narcolepsy. Finally, if your child does end up having both narcolepsy and ADHD, you will want to monitor treatment carefully. Both disorders are treated primarily using psychostimulants like amphetamine or methylphenidate (Ritalin). The drug modafinil (Provigil) is also sometimes used to treat narcolepsy. Adequate treatment of both disorders will likely mean a higher than usual dose of stimulants (or a combination of stimulants)--definitely watch out for adverse reactions so the dose can be adjusted if necessary. If different doctors see your child for each condition, you should make sure the doctors communicate regularly to ensure they are on the same page with the chosen treatment.