Attention deficit hyperactivity disorder (ADHD) is a mental disorder of the neurodevelopmental type.It is characterized by difficulty paying attention, excessive activity and acting without regards to consequences, which are otherwise not appropriate for a person's age.There is also often problems with regulating emotions. The symptoms appear before a person is twelve years old, are present for more than six months, and cause problems in at least two settings (such as school, home, or recreational activities).In children, problems paying attention may result in poor school performance. Additionally there is an association with other mental disorders and substance misuse. Although it causes impairment, particularly in modern society, many people with ADHD can have sustained attention for tasks they find interesting or rewarding (known as hyperfocus).
People with this disorder may have dissociative symptoms. For example, they may feel emotionally numb or disconnected from themselves. They may feel that they are not real.
The number of people with acute stress disorder is unknown. The likelihood of developing acute stress disorder is greater when traumatic events are severe or recurrent.
