What other disorders can present with inattention, distractibility, hyperactivity, or impulsivity besides attention‑deficit/hyperactivity disorder?

Differential Diagnosis of ADHD-Like Symptoms

When a child or adolescent presents with inattention, hyperactivity, or impulsivity that does not meet full ADHD criteria or when symptoms suggest alternative causes, you must systematically screen for emotional/behavioral disorders (anxiety, depression, PTSD, oppositional defiant disorder), developmental conditions (learning disabilities, autism spectrum disorder, language disorders), and physical conditions (sleep apnea, tic disorders, seizures). 1

Mandatory Screening Domains

The American Academy of Pediatrics requires evaluation across three specific domains before concluding symptoms represent ADHD 1:

Emotional and Behavioral Conditions

• Post-traumatic stress disorder (PTSD) manifests with impulsivity, hyperarousal, and attention difficulties that closely mimic ADHD but includes trauma-specific reexperiencing, avoidance, and emotion dysregulation that ADHD lacks 2
• Depression and anxiety disorders share hyperarousal and concentration difficulties with ADHD, occurring in approximately 14% of children with ADHD-like presentations, but lack the pervasive pattern present since before age 12 2, 3
• Anxiety disrupts focus through intrusive worries rather than primary attention deficits, causing inattention and restlessness that appear identical to ADHD symptoms 3
• Oppositional defiant disorder and conduct disorder co-occur in roughly 14% of cases, with prevalence rising with age 2
• Substance use, particularly marijuana in adolescents, produces effects mimicking ADHD including impulsivity and inattention 1, 2
• Adolescents may feign ADHD symptoms to obtain stimulant medications for academic or athletic performance enhancement 1, 2

Developmental Conditions

• Learning disabilities and language disorders frequently manifest as inattention and behavioral dysregulation appearing impulsive 1, 2
• Autism spectrum disorder presents with impulsive behaviors, difficulty with behavioral regulation, and inappropriate social responsivity that can mimic ADHD 1, 2, 4
• Children with autism spectrum disorder often exhibit elevated levels of both inattention and hyperactivity/impulsivity, complicating differential diagnosis 4
• Intellectual disability may present with motor restlessness, though children with intellectual disability typically exhibit significantly less inattention and hyperactive/impulsive behaviors than those with ADHD 2, 4

Physical and Medical Conditions

• Sleep disorders, including obstructive sleep apnea, produce daytime hyperactivity, inattention, and impulsive behavior that resolves with treatment of the underlying sleep problem 1, 2
• Tic disorders present with motor restlessness and impulsive movements that can be mistaken for hyperactivity 1, 2
• Seizure disorders, particularly absence seizures, mimic inattention episodes 2
• Reactive attachment disorder presents with inappropriate social responsivity and behavioral dysregulation appearing impulsive 2

Critical Diagnostic Algorithm

Before diagnosing ADHD, you must verify:

• At least 6 symptoms (5 for adolescents ≥17 years) persisting for ≥6 months 2
• Symptom onset before age 12 with documented or reliably reported manifestations from childhood 1, 2
• Information from at least two teachers (or coaches, school counselors, community activity leaders) plus parents/guardians demonstrating cross-setting impairment 1, 2
• Symptoms are not better explained by trauma, substance use, mood disorders, anxiety, or other psychiatric conditions 1, 2

Common Diagnostic Pitfalls

• Failing to obtain information from multiple settings before concluding ADHD criteria are met leads to misdiagnosis, as symptoms must be present across contexts 2, 3
• Relying solely on parent or teacher reports without corroborating information from multiple sources produces diagnostic errors 2
• Not establishing symptoms were present before age 12 in adolescents leads to misdiagnosis of conditions that emerged later, such as depression or substance-induced symptoms 1, 2
• Assigning ADHD diagnosis when symptoms are better explained by trauma, substance use, or other psychiatric conditions results in inappropriate treatment and missed opportunities to address the true underlying cause 1, 2
• Attributing all symptoms to ADHD when comorbid conditions exist leaves significant functional impairment unresolved, as the majority of children with ADHD-like symptoms meet criteria for another mental disorder 2, 3

When Diagnostic Uncertainty Exists

Refer to child psychiatrists, developmental-behavioral pediatricians, or child psychologists when:

• Complex comorbidities create diagnostic uncertainty 2
• Severe mood or anxiety disorders require specialized management before or alongside potential ADHD treatment 2
• Symptoms do not follow typical ADHD patterns despite meeting some criteria 1

Treatment Without Definitive Diagnosis

Behavioral interventions such as parent training in behavior management remain beneficial and do not require a specific diagnosis to help families manage hyperactive/impulsive behaviors that do not meet full ADHD criteria 1, 2, 3