Symptoms of ADHD

Three key features define attention-deficit hyperactivity disorder (ADHD)1 or hyperkinetic disorder (HKD)2 – inattention, hyperactivity and impulsivity – and the contribution of each to an individual’s presentation of ADHD varies from patient to patient.1 In some individuals, two or more features may contribute in equal measure; in others, one feature may predominate.1

As different features of ADHD can impair functioning and quality of life in different ways, it is important to accurately evaluate each patient’s unique symptomatic characteristics, using medical classification systems such as the Diagnostic and Statistical Manual of Mental Disorders – 5th edition (DSM-5TM) or the International Classification of Mental and Behavioural Disorders 10th revision (ICD-10).1,2 Whereas the ICD-10 characterises HKD by its “cardinal features” of impaired inattention and overactivity, the DSM-5TM categorises patients with ADHD by three main presentations: combined-type, predominantly inattentive-type and predominantly hyperactive-impulsive-type.1


Inattention is characterised as an individual moving between tasks without completing any one activity, seemingly losing interest in one task because they become diverted to another.1,2 Individuals with inattention are often easily distracted and forgetful, and experience difficulties when organising activities. At school, children with ADHD may struggle to listen and be frequently distracted; in the workplace, adults with ADHD may appear as if their mind is elsewhere and their work may be messy and performed carelessly (Figure 1).1

Figure 1: Typical symptoms of inattention1,2
Figure created from information in the DSM-5TM and ICD-10 classifications

Typical symptoms of inattention


Hyperactivity refers to excessive motor activity,1,2 and may present differently depending on the patient’s age.1 In children, it may present as the child running and jumping around at inappropriate times, getting up from a seat when he or she is supposed to remain seated, fidgeting and wriggling, or excessive talkativeness and noisiness.1,2 In adolescents and adults, hyperactivity may manifest as inner feelings of extreme restlessness and wearing others out with their activity (Figure 2).1

Figure 2: Typical symptoms of hyperactivity1,2
Figure created from information in the DSM-5TM and ICD-10 classifications

Typical symptoms of hyperactivity


Individuals with impulsive tendencies can be reckless and appear impatient, and are often disinhibited in social situations. They may find it difficult to wait their turn, intruding on or interrupting others’ activities or blurting out answers to a question before it has been completed (Figure 3).1,2

Figure 3: Typical symptoms of impulsivity1,2
Figure created from information in the DSM-5TM and ICD-10 classifications

Typical symptoms of impulsivity


View references

  1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fifth edition. Washington, DC: American Psychiatric Association, 2013.
  2. World Health Organization. The ICD-10 Classification of Mental and Behavioural Disorders. Available at: Last updated 1993; 1: 1-263. Last accessed March 2015.


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This booklet has been created to assist with clinical assessment of adult patients with ADHD using DSM-5TM criteria and the ASRS checklist.

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ADHD is often a lifelong neurobehavioural disorder, which may persist from childhood into adulthood.

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Interactive module: Rating scales used for the assessment of ADHD prior to formal diagnosis

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