Similarities Between Anxiety and ADHD
Overlapping Clinical Presentations
Anxiety and ADHD share multiple overlapping symptoms that frequently lead to diagnostic confusion, most notably inattention, restlessness, and difficulty with concentration. 1, 2
Core Symptom Overlap
Inattention is a cardinal feature of both conditions—anxiety disorders cause inattention through worry and hypervigilance, while ADHD causes inattention through primary executive dysfunction. 2
Restlessness and motor tension appear in both conditions, with anxiety producing physical tension and hyperarousal, while ADHD manifests as hyperactivity and impulsivity. 2
Concentration difficulties occur in both disorders but through different mechanisms—anxiety disrupts focus through intrusive worries, while ADHD involves primary deficits in sustained attention. 1, 2
Executive functioning deficits are present in both conditions, with emerging adults showing self-reported executive dysfunction related to both ADHD and anxiety symptoms, though inattention shows the strongest relationship. 3
High Comorbidity Rates
Approximately 25% of individuals with ADHD have comorbid anxiety disorders, making this one of the most common psychiatric comorbidities. 4
Around 14% of children with ADHD meet criteria for anxiety disorders, with rates increasing with age into adolescence and adulthood. 5
The majority of children presenting with ADHD-like symptoms meet criteria for another mental disorder, making systematic screening for anxiety essential rather than optional. 6
Shared Risk Factors and Functional Impairments
Both conditions significantly impair academic performance, with anxiety causing avoidance and concentration problems, while ADHD causes organizational difficulties and sustained attention deficits. 1
Peer relationship difficulties occur in both disorders—anxiety through social withdrawal and fear, ADHD through impulsivity and social skill deficits. 1
Family functioning is impaired in both conditions, requiring similar behavioral interventions such as parent training in behavior management. 6, 5
Sleep disturbances are common in both anxiety and ADHD, though sleep disorders themselves can mimic both conditions and must be ruled out. 2, 5
Diagnostic Challenges
Symptoms of anxiety can mimic ADHD, particularly generalized anxiety disorder, social anxiety, and separation anxiety, which cause inattention and restlessness that appear identical to ADHD symptoms. 2
ADHD symptoms can mimic anxiety, as the chronic stress of untreated ADHD often produces secondary anxiety symptoms that may be mistaken for a primary anxiety disorder. 1
Obtaining information from multiple settings is essential for both diagnoses, as symptoms must be present across contexts (home, school, work) to meet diagnostic criteria. 1, 2
Both conditions require ruling out trauma-related disorders, as PTSD and toxic stress can produce hyperarousal, concentration problems, and emotional dysregulation that mimic both ADHD and anxiety. 2, 5
Treatment Overlap
Behavioral interventions benefit both conditions, with cognitive-behavioral therapy effective for anxiety and parent training/behavioral modification effective for ADHD, though combined approaches are often needed. 7, 8, 9
Atomoxetine treats both ADHD and anxiety symptoms, making it uniquely positioned for comorbid presentations, as demonstrated in controlled trials showing no worsening of anxiety in ADHD patients with comorbid anxiety disorders. 10, 7, 9
Stimulant medications for ADHD frequently alleviate comorbid anxiety symptoms, contrary to earlier concerns, with most patients experiencing improvement in both symptom domains. 7, 8, 9
Comorbid Presentation Characteristics
When ADHD and anxiety co-occur, patients show greater executive functioning deficits than those with either condition alone, particularly in self-regulation of emotion and self-organization/problem solving domains. 3
Comorbid ADHD and anxiety is associated with higher degrees of impairment and poorer long-term prognosis than either condition alone, requiring more intensive multimodal treatment. 8, 4
The comorbid condition may represent a distinct neuropsychiatric entity involving dysregulation in both anxiety and ADHD domains, rather than simply two separate disorders occurring together. 8
Critical Diagnostic Pitfalls
Failing to systematically screen for both conditions leads to misdiagnosis, as approximately 10% of adults with recurrent depression and anxiety disorders have undiagnosed ADHD that prevents treatment response. 1
Attributing all symptoms to one condition when both are present results in inadequate treatment, as addressing only ADHD or only anxiety leaves significant functional impairment unresolved. 1, 2
Not establishing symptom onset before age 12 for ADHD can lead to misdiagnosing anxiety-related attention problems as ADHD in adolescents and adults. 1, 2