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Symptoms and Definition of Attention-Deficit/ Hyperactivity Disorder (ADHD)

Attention-Deficit/ Hyperactivity Disorder (ADHD) begins in childhood, and some symptoms of the condition must begin before age 7 in order for a diagnosis to be made. The symptoms fall into three general categories:


  • Generally fails to give close attention to details or makes careless mistakes
  • Has difficulty paying attention for long in tasks or play activities
  • Often does not seem to listen when spoken to directly
  • Has difficulty following steps of instructions (not due to oppositional behavior or difficulty understanding instructions)
  • Has difficulty being organized in tasks and activities
  • Dislikes or tends to avoid tasks that require sustained concentration, like schoolwork
  • Often misplaces items necessary for tasks or activities, like toys or school and work material
  • Is easily distracted by other things going on
  • Tends to be forgetful in daily activities


  • Often fidgets or has trouble sitting still
  • Has trouble remaining seated for long periods of time, and will leave seat even in situations where it is expected to remain seated
  • Runs and climbs about excessively in situations where this is not appropriate, or in adolescence and adulthood, often feels restless
  • Often has difficulty playing or doing activities quietly
  • Often is "on the go" or seems full of energy and not interested in stopping
  • Tends to talk excessively


  • Often blurts out answers before questions have been completed
  • Has difficulty awaiting turn
  • Tends to interrupt or intrude on others, such as butting into conversations or games

A diagnosis of ADHD Inattentive Type is made when an individual has at least 6 of the Inattention symptoms described above for at least 6 months.

A diagnosis of ADHD Hyperactive-Impulsive Type is made when an individual has a total of at least 6 of the symptoms from the Hyperactivity and Impulsivity groups described above for at least 6 months.

A diagnosis of ADHD Combined Type is made when an individuals meets the criteria for both Inattentive and Hyperactive-Impulsive Types.

By definition, the symptoms of ADHD need to occur in more than one setting, such as school, work, or home, and need to interfere in a significant way with how one functions in these settings. The symptoms should also not occur exclusively during the course of an Autistic Spectrum Disorder or a Psychotic Disorder, and should not be better accounted for by other psychiatric conditions like Bipolar Disorder, Anxiety Disorders, Dissociative Disorders or Personality Disorders.

The above list of symptoms is based primarily on how ADHD manifests in children, and some have argued that it does not fully capture how the condition appears in adulthood. Additional symptoms that are common among adults with ADHD include procrastination, overreacting to frustration, poor motivation, insomnia, and time-management difficulties [ref].


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