Attention-deficit/hyperactivity disorder (ADHD) frequently co-occurs with anxiety disorders, making it an important area for clinicians to understand. Research shows that roughly 20 to 25% of children with ADHD develop an anxiety disorder. By adulthood, this comorbidity rises significantly, with around 45 to 50% of adults with ADHD experiencing an anxiety disorder at some point. Understanding the mechanisms linking ADHD and anxiety is key to effective assessment and intervention.

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ADHD Symptoms and Risk Factors for Anxiety

ADHD is characterised by inattention, distractibility, poor follow-through on tasks, forgetfulness, and hyperactive-impulsive behaviours. Inattention in ADHD is primarily outwardly directed, meaning individuals are highly responsive to environmental stimuli. This contrasts with cognitive disengagement syndrome (CDS), formerly known as sluggish cognitive tempo, in which inattention is internally directed, marked by daydreaming, rumination, and hypoactivity. CDS shows a particularly strong association with anxiety, independent of ADHD.

Over time, ADHD can increase the risk of anxiety disorders, particularly social anxiety. Untreated ADHD often contributes to difficulties with daily functioning, repeated setbacks, and cumulative negative experiences. These experiences can lead to anticipatory anxiety—fear or worry about future situations based on past difficulties.

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Mechanisms Linking ADHD and Anxiety

Two primary mechanisms explain how ADHD contributes to anxiety:

1. Emotion Dysregulation – Executive function deficits in ADHD, especially in emotional self-regulation, make individuals more reactive to everyday stressors. This can produce mild anxiety symptoms even in the absence of a formal anxiety disorder.
2. Cumulative Life Challenges – Repeated difficulties in work, relationships, or academic settings can create a cycle of stress and anticipatory anxiety. Individuals may develop fear or worry about future situations in which they anticipate failure or difficulties.

While ADHD can contribute to mild or situational anxiety, it is less likely to cause classical anxiety symptoms such as panic attacks, agoraphobia, or generalized excessive worry unrelated to specific challenges. Social phobia is the exception, often appearing alongside ADHD due to repeated negative social experiences.

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Clinical Implications

Effective treatment requires differentiating the type of anxiety and its underlying causes:

• ADHD-Related Anxiety – Mild anxiety arising from poor emotional regulation or anticipatory anxiety linked to cumulative life challenges can often be mitigated with standard ADHD treatments. Cognitive-behavioral therapy (CBT), ADHD coaching, stimulant or non-stimulant medication, and mindfulness practices targeting executive function deficits may improve both functional outcomes and associated anxiety.
• Primary Anxiety Disorders – Anxiety symptoms that are classical, pervasive, or unrelated to ADHD-driven experiences may require standard anxiety-focused therapies. These include CBT targeting maladaptive thought patterns, anti-anxiety medications, and traditional mindfulness or relaxation techniques. Comorbid conditions such as PTSD may also require targeted interventions.

Interestingly, treating primary anxiety symptoms can sometimes improve ADHD-related difficulties, particularly cognitive disengagement and attention challenges, indicating the complex bidirectional relationship between these conditions.

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Key Takeaways for Clinicians

• ADHD frequently co-occurs with anxiety, and risk increases with age and cumulative life challenges.
• Inattention in ADHD is externally directed, whereas cognitive disengagement syndrome involves internal preoccupation and is more strongly linked to anxiety.
• Executive function deficits and emotional dysregulation in ADHD contribute to mild anxiety, while repeated life setbacks increase anticipatory anxiety.
• ADHD therapies can address anxiety secondary to ADHD, but primary anxiety disorders often require separate interventions.
• Comprehensive assessment should consider overlapping symptoms, comorbidities, and the developmental trajectory of both ADHD and anxiety.

Clinicians should adopt an individualized approach, combining ADHD management strategies with targeted interventions for anxiety when needed. Understanding the nuances of these comorbidities allows for more effective treatment planning and improved patient outcomes.