What is ADHD? Robert D. Smith, PhD Attention-deficit/hyperactivity   disorder   (ADHD)   is   a   developmental   brain   disorder   with   symptoms   of   hyperactivity,   impulsiveness and/or inattention. Many   of   the   symptoms   of   ADHD   occur   from   time   to   time   in   everyone.   For   people   with   ADHD,   the   number   and   frequency   of   these symptoms   is   greater   than   most   people   and   significantly   impairs   educational   achievement,   career   success   and   life   success   in general. Symptoms The distinct symptom DSM-5 categories of ADHD are: Impulsiveness:    acting   before   thinking   of   consequences,   jumping   from   one   activity   to   another,   disorganization,      tendency   to interrupt other peoples' conversations. Hyperactivity:    restlessness,   often   characterized   by   an   inability   to   sit   still,   fidgeting,   squirminess,   climbing   on   things,   restless sleep. Inattention:  easily distracted, day-dreaming, not finishing work, difficulty listening. The DSM-V identifies three ADHD subtypes: (1) Inattentive; (2) hyperactive/impulsive; and (3) combined. There   is   growing   discussion   between   experts   that   the   inattentive   type   may   be   two   different   types.   A   Unique   ADD   Type,   not   yet officially recognized is a distinctly different information processing disorder characterized by sluggish cognitive tempo. Diagnosis   is   based   on   criteria   specified   in   the   DSM-V   or   the   ICD-10.   No   objective   test   has   been   identified   as   sufficient   evidence to   make   a   diagnosis   of   ADHD.   Diagnosis   is   therefore   based   on   clinical   judgment.   However,   neuropsychological   tests   can   provide significant objective evidence supporting clinical judgment. In addition, impairment of executive functioning is often present. The   International   Statistical   Classification   of   Diseases   and   Related   Health   Problems   (ICD-10)   are   published   by   the   World   Health Organization.   The   ICD-10   provides   criteria   and   codes   to   classify   diseases.   The   American   Psychiatric   Association   used   the   general outline   of   mental   disorder   classifications   in   the   ICD-10   and   tried   to   improve   the   diagnostic   criteria   and   developed   the   Diagnostic and Statistical Manual of Mental Disorders (DSM-V). In   North   America,   the   DSM-V   criteria   are   used   to   make   a   diagnosis   of   ADHD,   while   European   countries   usually   use   the   ICD-10. Previous     editions     of     the     ICD     series     have     used     the     term     Attention     Deficit     Disorder     (ADD)     with     and     without hyperactivity/impulsiveness.   The   DSM-V   has   adopted   the   term   Attention   Deficit/Hyperactivity   Disorder   (ADHD)   with   and   without hyperactivity/impulsiveness.   The   two   terms   mean   essentially   the   same   thing   and   have   resulted   in   confusion.   However,   the   use   of the term ADD to refer to ADHD, predominantly inattentive type makes good common sense.