Symptoms and signs of ADHD

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Woman trembling with motor instability

Difficulty in not being distracted and maintaining attention during a long task. Difficulties in selective attention, easily distracted by stimuli irrelevant to the task being performed.

Person with difficulty in doing homework

Making careless mistakes at school or at work, or during other activities.

Child asking questions to an adult

Seeming not to listen when spoken to directly.

Stress and occupational anxiety for a long time

Difficulties in organising tasks and activities and in prioritising. Tendency to procrastinate (delaying performance of tasks).

Pencil and notebook to write down words or phrases you don't understand

Losing and forgetting objects needed for tasks or activities (e.g., toys, school exercises or books).

Person with bipolar disorder who won't stop talking

Excessive and/or inappropriate, unnecessary and unintentional motor and/or vocal activity. Talking excessively. Not modifiable by social environment requirements.

A person who stands up after sitting in a chair

Difficulty sitting still or restlessness of hands and feet. Leaving your seat in class or in other situations when you are expected to remain seated.

Person running

Running or jumping excessively in inappropriate situations (this may be limited to subjective feelings of restlessness or more limited motor restlessness in adolescents and adults. For example, moving your feet or hands, moving objects with your fingers).

Person with dysphonia

Being inappropriately noisy or difficulty playing or engaging in leisure activities calmly.

Person who has difficulty knowing the difference between fantasy and reality

Inability to inhibit behaviours, inability to delay gratifications, responding to questions before they have been completed. Being very insistent.

Two men and one woman

Difficulty in waiting your turn (in queues or other group situations).

Adult and child playing a ball game

Interrupting or intruding on the activities of others (e.g., butting into conversations or games).

Not all these symptoms are always present, and can appear in different combinations. Sometimes these behaviours can be confused with particularities in the child's personality. It is important to keep in mind that a disorder can be considered only when the child's manifestations occur more frequently than in most children of the same age and with the same level of development. They must also be taken into account if they affect the person's work or social or family life.  

Some of the warning signs that can help identify this disorder are:  

  • Being described as "lazy" or "rude".  
  • Parents feel overwhelmed, due to requiring excessive supervision.  
  • Low academic performance, the comment "could do more" by teachers is frequent.  
  • Receives many warnings for not turning in assignments when due.  
  • Is often disorganised in writing and has problems with presentation.
  • He is often punished at school.  
  • He has frequent conflicts with classmates.  

Similar but apparently less severe features may occur in girls.


These symptoms are not consistent, but vary and can combine with, or be replaced by, each other depending on the stage of life. Some examples are:  

  • As infants, children with ADHD are more aggressive in games and have more tantrums.
  • At school, they tend to talk excessively, interrupt others or submit incomplete homework.  
  • In adolescence, they may have low self-esteem, be disorganised or internally restless, with physical hyperactivity symptoms being reduced.

More frequently than others, people with ADHD also have other mental disorders. Some associations observed are:  

  • Depressive disorder: This disorder is present with ADHD in 10-40% of cases.
  • Anxiety disorder: This disorder is present with ADHD in 34% of cases, rising to 40% in the adult population. The most frequent anxiety disorders in people with ADHD are: separation anxiety, panic disorder, obsessive-compulsive disorder (OCD) and general anxiety.
  • Autism Spectrum Disorder (ASD): Of children with ASD, inattentive type ADHD symptoms are observed in 33% and combined type ADHD symptoms in 26%.
  • Substance Abuse Disorder (SAD): approximately 23% of subjects with SAD have symptoms of ADHD. In some investigations that include all kinds of toxins and alcohol, 52% of patients diagnosed with ADHD are identified with substance use disorder.
  • Tic disorders and Tourette Syndrome: Most children with this syndrome have associated ADHD; while, a minority of children with ADHD also have tics.
  • Oppositional Defiant disorder: This disorder occurs in 2-16% of the general child population but 20-40% of children with ADHD.

Substantiated information by:

Marta Garcia Giral
Montse Vila
Rosa Nicolau

Published: 18 February 2022
Updated: 18 February 2022

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