Teachers with special education degrees also educate students with behavioral challenges such as ADHD and the related condition, attention deficit disorder (ADD). Students with behavioral challenges often have issues with appropriate communication, social interaction, and/or sensory behaviors. There are a number of medical conditions that result in challenging behavior, including ADHD and ADD. Both of these disorders are difficult to diagnose, but can generally be described as being fidgety with hands or feet, talking excessively, forgetting daily activities, having trouble sitting still, having trouble controlling behavior, having trouble paying attention in class, and making careless mistakes on school work. Such qualities can be found in many children, but a professional must determine if these characteristics have reached a level beyond normal for the child's age and become a disability. It is unclear what causes ADHD and ADD, but the conditions make a general education classroom experience quite difficult. Some critics believe that neither ADHD nor ADD exist and that students so diagnosed are behaving inappropriately and just lack discipline. Another concern about a diagnosis of ADHD and ADD includes what many believe is an excessive number of children receiving medication for the disorder instead of learning how to control themselves and manage their impulses.