In order to be diagnosed with AD/HD, the symptoms generally occur before the person is seven years old and must last longer than six months. Also, the person must experience these symptoms in at least two environments, like at school, home, work or some other social setting.
AD/HD often runs in families. According to research, if one person in a family has AD/HD, there is a 25% to 35% chance that another family member will also have the disorder.