ADHD: Overlooked Cause of Persistent Anxiety and Depression in Adults

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CLINICAL REFLECTIONS

Case Vignette

“Simon,” a 21-year-old man, presents for an evaluation of treatment-resistant anxiety. He experiences psychological anxiety, which interferes with his focus and concentration, causing difficulties with initiating and sustaining tasks. A review of his past psychiatric history reveals that he began seeing a therapist for panic attacks and severe anxiety that seemed to come out of nowhere when he was in middle school. He had consulted 3 different psychiatrists but had not found any of their treatments effective. He denies any history of mania or psychosis.

He received cognitive behavior therapy and was subsequently treated with various psychiatric medications, including buspirone, fluoxetine, escitalopram, phenelzine, mirtazapine, bupropion, aripiprazole, quetiapine, olanzapine, pregabalin, clonazepam, lorazepam, valproate, lamotrigine, lithium, and ketamine. However, Simon reports no psychological improvement with these medications. On the contrary, he experienced multiple adverse effects, including a panic-like electric shock reaction with phenelzine, a dystonic reaction with antipsychotics, and 2 grand mal seizures with bupropion. At the time of evaluation, Simon was taking buspirone 30 mg twice daily, pregabalin 150 mg, lamotrigine 200 mg, lithium 450 mg at night, and mirtazapine 30 mg. Simon came in frustrated, requesting to discontinue all his medications. After a thorough evaluation, including a review of his developmental history, it was found that he had exhibited characteristics of inattention and hyperactivity since elementary school. A subsequent Jasper/Goldberg Adult ADD Screening Examination indicated undiagnosed attention-deficit/hyperactivity disorder (ADHD). Simon was therefore started on viloxazine 100 mg, titrated to 200 mg over 1 week while continuing lamotrigine 200 mg and tapering off all other medications.

ADHD in Adulthood

ADHD is a multifactorial and clinically heterogeneous disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. It can impose significant financial burdens and stress on families and is also associated with adverse academic and vocational outcomes. Although ADHD is recognized as a childhood-onset neurodevelopmental disorder, its prevalence in adults should also be acknowledged.

A recent meta-analysis has reported that the prevalence of ADHD in children and adolescents is estimated to be 5.29%, the prevalence of ADHD in adults aged 19 to 45 years is estimated to be 2.5%. Approximately 15% children with ADHD will persist into their adulthood, with 40% to 60% partially remitted.¹ In some cases, adults remain undiagnosed until they reach their 30s or 40s, only discovering they have ADHD after their children are diagnosed. A national wide investigation done in an East-Asian country indicated a percentage of 34.7% in first year university students presented with symptoms suggestive of probable ADHD.² Even in European countries, where ADHD should have been better recognized and treated, the prevalence of undiagnosed ADHD in adult psychiatric patients was 9.27%, and “hidden” ADHD is associated with an increased suicide risk among these patients.³

Previous review has emphasized that ADHD can persist throughout one's lifespan and often presents as a chronic condition. If left untreated, the symptoms of ADHD can lead to significant psychosocial impairment,⁴ and leading to maladaptive behaviors including self-medicating by using recreational drugs, alcohol, and nicotine.⁵

Diagnosing adult ADHD is challenging due to limited guidelines and consensus. Once seen as a childhood disorder, ADHD is now recognized to persist into adulthood, but this shift has outpaced clinical approaches, leading to inconsistent diagnosis.

Key challenges in adult ADHD diagnosis include:

1. Symptom overlap. ADHD symptoms in adults (eg, inattention, impulsivity) often overlap with conditions like depression and anxiety, complicating diagnosis.

2. Retrospective diagnosis. Adult diagnosis relies on evaluating childhood symptoms, which may have been undiagnosed or misunderstood.

3. Cultural/societal differences. ADHD prevalence varies by region due to stigma and health care differences, leading to "hidden" cases.

4. Gender bias. Women are often underdiagnosed as their symptoms are less hyperactive and more inattentive, sometimes mistaken for stress or mood disorders.

These are some of things a clinician should keep in mind while considering a patient to be suffering from adult ADHD. These include:

1. Comprehensive history. Gather detailed information on childhood behavior, academic issues, and coping strategies. Family history of ADHD may provide further insights.

2. Use diagnostic tools. Employ standardized tools like the Adult ADHD Self-Report Scale (ASRS) to assess symptoms.

3. Assess developmental milestones. Examine the developmental trajectory, noting if symptoms persisted into adulthood even with coping strategies.

4. Evaluate functional impairment. Diagnose ADHD only if symptoms impair major areas of life (work, relationships, etc).

5. Rule out other conditions. Conduct differential diagnoses to exclude psychiatric conditions with similar symptoms.

6. Psychoeducation and collaboration. Educate patients on ADHD as a lifelong condition and collaborate with other specialists for comprehensive care.

7. Consider subtle symptoms. Watch for less overt symptoms in adults, like procrastination, emotional dysregulation, or chronic lateness.

Improving global ADHD guidelines and diagnostic consistency requires cross-cultural studies and refinement of tools like the DSM-5. Clinicians should combine thorough history-taking, structured tools, and functional assessment to accurately diagnose and treat adult ADHD. Education and addressing the stigma are also key to bridging the gap in adult ADHD diagnosis and care.

Psychological Burden

The underlying ADHD symptoms experienced by adults can lead to functional impairments, affecting their academic and vocational performance, daily activities, and social interactions. These impairments may further contribute to a significant psychological burden.

In today's fast-paced modern society, patients' procrastination, inattentiveness, and disruptive behaviors, if unnoticed and untreated, can place them in difficult situations, leading to significant psychosocial stress, which may further contribute to the development of other psychiatric disorders. Undiagnosed ADHD can have negative impacts on self-esteem and self-worth,⁵ and is associated with higher rates of current depression, alcohol abuse, and greater emotional and interpersonal difficulties when compared with patients who do not have ADHD.^6,7 Research has shown that undiagnosed adults with potential ADHD symptoms may have a higher coexistence of mental comorbidities, sleep problems, and physical comorbidities, they also experience greater work productivity impairment, increased health care resource usage, and lower health-related quality of life.⁸

ADHD and its Comorbidities

Prevalence of ADHD is 2.5% in adults.¹ Individuals with ADHD have symptoms like deficient inhibitions, problems with memory, decision-making, and emotional decision-making, which can lead to a misdiagnose as they are symptoms of other conditions. ADHD shares symptomatology with major depressive disorder (MDD; low hedonic tone, irregular sleep, and appetite), generalized anxiety disorder (GAD; fidgeting, irritability), bipolar disorder (episodic fluctuations, excessive talking), and substance use disorder (SUD; social withdrawal) (as illustrated in Figure). ADHD has an especially high prevalence with bipolar disorder, with rates ranging from 9.5% to 21.2%.⁹ With MDD, ADHD prevalence has been reported to be between 9% to 16%.¹⁰ There is also an increased risk of ADHD in patients of GAD, with risk rising by about 50% more than in the general population.¹¹ ADHD is more common in patients with social anxiety. Finally, SUD is about twice as likely in patients with ADHD. It is bidirectional, arising due to neurological factors, increased impulsivity, other comorbidities, and any attempts to self-medicate.

Figure. Adult ADHD and Various Comorbid Disorders

ADHD is a common but often underrecognized and undertreated psychiatric disorder in adults, presenting with symptoms from other possible diagnoses. Screening for ADHD in adults presenting with these comorbidities can identify patients who may benefit from targeted management. While ADHD in adults presents variably, it can often be detected with a few key clinical questions and validated assessment scales like Adult ADHD Self-Report Scale (ASRS) or the Conners' Adult ADHD Rating Scales (CAARS). Early and effective treatment of ADHD can significantly improve long-term psychiatric and functional outcomes. When ADHD coexists with other psychiatric conditions, the more severe disorder should be prioritized in treatment. In the coming years, more work on genetic and organic causes of ADHD may help identify new points for targeted treatment and ultimately help the patients.¹²

Concluding Thoughts

Identifying ADHD correctly is essential, especially when it is hidden by cooccurring illnesses. Properly identifying ADHD, particularly when it is masked by comorbid conditions, plays a significant role in developing an appropriate treatment plan. Such cases have been documented, demonstrating the challenges in diagnosing ADHD when other disorders are present.¹³ This marks the importance of screening for ADHD, particularly in patients with treatment-resistant anxiety or MDD. In these situations, a misdiagnosis may result in the patient receiving poor treatment and unsuitable medication, worsening their condition. Therefore, a thorough evaluation for ADHD should be a standard component of the diagnostic process in patients who do not respond to conventional therapies for anxiety or MDD. Identifying ADHD early improves the efficacy of treatment and enhances the overall quality of life for the patient by addressing the cause of their symptoms.

Dr Parikh is a faculty member at Weill Cornell Medical College and Second Arc Psychiatric Associates in White Plains, New York. Dr Chen works in the Department of Psychiatry at Second Xiangya Hospital of Central South University in Changsha, China. Dr Patel works at the Government Medical College and New Civil Hospital in Gujarat, India.

References

1. Posner J, Polanczyk GV, Sonuga-Barke E. Attention-deficit hyperactivity disorder. Lancet. 2020;395(10222):450-462.

2. Al-Yateem N, Slewa-Younan S, Halimi A, et al. Prevalence of undiagnosed attention deficit hyperactivity disorder (ADHD) symptoms in the young adult population of the United Arab Emirates: a national cross-sectional study. J Epidemiol Glob Health. 2024;14(1):45-53.

3. Bitter I, Mohr P, Balogh L, et al. ADHD: a hidden comorbidity in adult psychiatric patients. Atten Defic Hyperact Disord. 2019;11(1):83-89.

4. Zalsman G, Shilton T. Adult ADHD: a new disease? Int J Psychiatry Clin Pract. 2016;20(2):70-76.

5. Attoe DE, Climie EA. Miss. Diagnosis: a systematic review of ADHD in adult women. J Atten Disord. 2023;27(7):645-657.

6. Able SL, Johnston JA, Adler LA, Swindle RW. Functional and psychosocial impairment in adults with undiagnosed ADHD. Psychol Med. 2007;37(1):97-107.

7. Okumura Y, Yamasaki S, Ando S, et al. Psychosocial burden of undiagnosed persistent ADHD symptoms in 12-year-old children: a population-based birth cohort study. J Atten Disord. 2021;25(5):636-645.

8. Naya N, Tsuji T, Nishigaki N, et al.The burden of undiagnosed adults with attention-deficit/hyperactivity disorder symptoms in Japan: a cross-sectional study. Cureus. 2021;13(11):e19615.

9. Wingo AP, Ghaemi SN. A systematic review of rates and diagnostic validity of comorbid adult attention-deficit/hyperactivity disorder and bipolar disorder. J Clin Psychiatry. 2007;68(11):1776-1784.

10. McIntosh D, Kutcher S, Binder C, et al. Adult ADHD and comorbid depression: a consensus-derived diagnostic algorithm for ADHD. Neuropsychiatr Dis Treat. 2009;5:137-150.

11. Mancini C, Van Ameringen M, Oakman JM, Figueiredo D. Childhood attention deficit/hyperactivity disorder in adults with anxiety disorders. Psychol Med. 1999;29(3):515-525.

12. Katzman MA, Bilkey TS, Chokka PR, et al. Adult ADHD and comorbid disorders: clinical implications of a dimensional approach. BMC Psychiatry. 2017;17(1):302.

13. Toole KP, Frank C.Young adolescent with undiagnosed ADHD-inattentive presentation and co-morbid anxiety and depression: a case report. J Pediatr Nurs. 2024;78:e250-e259.