What are the signs and symptoms of Attention Deficit Hyperactivity Disorder (ADHD)?

Signs and Symptoms of ADHD

ADHD presents with three core symptom domains—inattention, hyperactivity, and impulsivity—that must persist for at least 6 months, cause functional impairment in at least two settings, and have onset before age 12 years. 1, 2

Core Symptom Categories

Inattentive Symptoms

Adults with ADHD predominantly present with inattentive symptoms rather than hyperactive symptoms. 1, 3 The following inattentive manifestations must be evaluated:

• Poor attention to detail and frequent careless mistakes in work or other activities 1
• Difficulty concentrating or sustaining attention on tasks, even during conversations 1, 2
• Appears preoccupied with difficulty shifting focus, even when spoken to directly 1
• Difficulty completing tasks due to getting distracted or side-tracked 1
• Organizational challenges resulting in chronic lateness for appointments or deadlines, messiness, and disorganized work 1, 2
• Reluctance to engage in tasks requiring sustained mental effort, such as preparing reports or reviewing lengthy papers 1, 4
• Difficulty keeping track of personal belongings or items required for task completion 1
• Easily distracted by extraneous stimuli 1
• Forgetfulness in daily activities 1, 4

Hyperactive-Impulsive Symptoms

The hyperactive-impulsive presentation includes the following manifestations:

• Frequent fidgeting, such as tapping a desk or squirming in seat 1, 4
• Difficulty sitting still for prolonged periods, particularly in structured settings 1
• Feeling of inner restlessness or agitation (particularly prominent in adults and adolescents) 1, 2
• Often loud and disruptive in social or work settings 1
• Always on the go, making it difficult for others to keep up 1
• Talks excessively 1, 4
• Frequently interrupts others with difficulty restraining themselves from sharing perspectives or waiting their turn in conversation 1, 4
• Highly impatient and unable to wait turn 1, 4

Diagnostic Requirements

At least 5 symptoms from either the inattentive or hyperactive-impulsive category (or both) must be present in adults age 17 and older; 6 or more symptoms are required for those under age 17. 1

The following diagnostic criteria must all be met:

• Symptom duration: An ongoing pattern must persist for at least 6 months 1, 2, 4
• Age of onset: Several symptoms must have been present before age 12 years 1, 2, 4
• Multiple settings: Symptoms must be present in 2 or more settings (home, work, school, social environments) 1, 2
• Functional impairment: Clear evidence that symptoms interfere with or reduce quality of functioning in interpersonal, occupational, or academic domains 1, 2
• Not better explained by: Oppositional behavior, defiance, hostility, failure to understand tasks, or another mental disorder such as psychotic disorder, mood disorder, anxiety disorder, dissociative disorder, personality disorder, or substance intoxication/withdrawal 1

Age-Specific Presentations

Preschool Children (Ages 4-5)

Diagnosis is more challenging due to developmental variability, but extreme hyperactivity and inability to sit during structured activities may indicate ADHD. 2

School-Age Children (Ages 6-11)

Symptoms become more apparent in structured settings, including disruptive classroom behavior and difficulty completing homework or classwork. 2

Adolescents (Ages 12-18)

Overt hyperactivity declines but internal restlessness persists; inattentive symptoms become more prominent and problematic, with hyperactive presentation shifting to more subtle manifestations including impulsive decision-making. 2

Adults

Adults are more likely to present with predominantly inattentive symptoms, including chronic disorganization, difficulty with sustained mental effort, and emotional dysregulation. 1, 3, 5, 6

Screening and Assessment Tools

Use the Adult ADHD Self-Report Scale (ASRS-V1.1) Part A as the initial screening tool, which contains 6 questions (4 assessing inattention, 2 assessing hyperactivity/impulsivity). 1, 3

• A screen is positive when a patient checks "often" or "very often" for 4 or more of the 6 questions 1
• The complete ASRS contains 18 total items aligned with DSM-5 criteria, with 9 items assessing inattentive symptoms and 9 items assessing hyperactive-impulsive symptoms 3
• The ASRS should be used as a screening tool, not a standalone diagnostic instrument, and requires comprehensive clinical evaluation including verification of impairment across multiple settings 3

Context-Dependent Symptom Variations

ADHD symptoms show relative context-dependency despite their chronicity, which can complicate diagnosis during clinical examination. 7

• Symptoms may be less severe or completely absent in unfamiliar environments, dual relations, or calm settings where the child receives attention and positive reinforcement 7
• Classroom situations with high stimulation levels (noise, visual distractors, large class size) are likely to reveal or accentuate instability, impulsivity, and inattention 7
• Preference for immediate gratification and delay aversion may explain why ADHD patients show satisfactory attentional capacities in certain activities (video games, TV) while showing impairment in school work or effortful tasks 7

Critical Diagnostic Pitfalls to Avoid

Diagnosis requires information from multiple observers across different settings, including parent/guardian reports, teacher reports, and direct observation. 2

Alternative Explanations to Rule Out:

• Sleep disorders 2
• Anxiety and depression 2, 8
• Learning disabilities 2, 8
• Substance use 2
• Trauma and toxic stress 2
• Autism spectrum disorders 2

Common Comorbidities to Screen For:

The majority of children with ADHD meet criteria for another disorder, including:

• Oppositional defiant disorder and conduct disorder 1, 2
• Anxiety and depression (rates of comorbid psychiatric problems range from 12-60%) 2, 8
• Learning and language disorders 2, 8
• Tic disorders 2
• Substance use disorders 2

Around 10% of adults with recurrent depression and/or anxiety disorders have ADHD, and treatment of depression and anxiety will likely be inadequate to restore optimal quality of life for those with unaddressed ADHD. 1

Additional Clinical Considerations

• Heritability: ADHD has heritability rates of 70-80%, making it one of the most heritable neuropsychiatric conditions; positive family history significantly increases risk 2
• Chronic nature: Unlike depression, which is most often episodic, ADHD is a chronic condition that often becomes more challenging to manage as individuals deal with increased demands of pregnancy, parenting, work, and adult responsibilities 1
• Collateral history: Obtaining collateral history from parents or reviewing school records is necessary to document childhood manifestations, particularly when evaluating adults, as patients often have poor insight into their symptoms and may underestimate severity 2