Treatment of Adults with ADHD and Comorbid Anxiety

Introduction to Stimulant Therapy

The American Academy of Child and Adolescent Psychiatry recommends starting with a stimulant medication, such as methylphenidate or amphetamine, as first-line treatment for adults with ADHD and comorbid anxiety, as stimulants are highly effective for ADHD and can improve anxiety symptoms in most patients with this combination 1
The Multimodal Treatment of Attention Deficit Hyperactivity Disorder (MTA) study and subsequent trials demonstrate that ADHD patients with comorbid anxiety have better treatment responses to stimulants than those without anxiety 1

Stimulants have a 70-80% response rate for ADHD treatment, allowing for quick assessment of whether both ADHD and anxiety symptoms improve 2
Stimulants have a rapid onset of action, typically within days, and often improve anxiety symptoms indirectly by reducing ADHD-related functional impairment 2, 1
Methylphenidate and amphetamines have the strongest effect sizes for reducing core ADHD symptoms 1

The American Academy of Child and Adolescent Psychiatry recommends using extended-release preparations to achieve all-day coverage and minimize rebound symptoms in late afternoon/evening 1
The American Academy of Child and Adolescent Psychiatry recommends methylphenidate 5-20 mg three times daily (or equivalent long-acting formulation) or dextroamphetamine 5 mg three times daily to 20 mg twice daily (or equivalent long-acting formulation like lisdexamfetamine) 2

If both ADHD and anxiety improve with stimulant monotherapy, continue stimulant monotherapy without modification, and monitor for 2-4 weeks to assess full response 1, 2
If anxiety persists despite ADHD improvement, continue the stimulant and optimize the SSRI dose (e.g., Lexapro 10-20 mg daily range) before adding additional agents, as SSRIs are first-line for anxiety 3, 2

Atomoxetine may be considered instead of stimulants in specific contexts, such as history of substance use disorder, severe anxiety, or pre-existing sleep disorders, with dosing at 60-120 mg/day and monitoring for suicidality 1

For stimulants, monitor height, weight, blood pressure, pulse, appetite, sleep, and anxiety symptoms, as stimulants can improve anxiety symptoms in most patients 1
For atomoxetine, monitor appetite, weight, suicidality, and blood pressure, as atomoxetine can have a slower onset of action and lower effect size compared to stimulants 1