Attention deficit hyperactivity disorder (ADHD or AD/HD or ADD) is a developmental disorder. It is characterized primarily by "the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone" and symptoms starting before seven years of age. ADHD is the most commonly studied and diagnosed psychiatric disorder in children, affecting about 3 to 5 percent of children globally and diagnosed in about 2 to 16 percent of school aged children. It is a chronic disorder with 30 to 50 percent of those individuals diagnosed in childhood continuing to have symptoms into adulthood. Adolescents and adults with ADHD tend to develop coping mechanisms to compensate for some or all of their impairments. It is estimated that 4.7 percent of American adults live with ADHD. Standardized rating scales such as WHO's Adult ADHD Self-Report Scale can be used for ADHD screening and assessment of the disorder's symptoms' severity. . Here is a test for attention disorder. Attention Deficit Disorder (ADHD) Test - Psych Central Any of us can have it. My score was 45 which puts me in a mild category of this. I never knew about this till recently where I investigated for another reason. When I read more about it, I realized why I was behaving in a certain manner when I was a kid and to an extent even today.