From Childhood Impairments to Delayed Diagnosis: A Series of Adult ADHD Cases

Abstract

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neuro-developmental disorder typically characterized by, but not limited to, inattention, hyperactivity, and impulsivity. Persistence into adulthood is reported in at least half of those diagnosed in childhood with significant functional impairments in the form of inefficiency, distractibility, internal restlessness, and planning difficulties—often normalized or reframed as personality traits, anxiety, or low motivation. Academic, vocational & interpersonal functioning may be dependent on many factors and could be maintained by various positive psychosocial and intellectual scaffolds. But, transition to adolescence and adulthood, by its very nature, takes off some of these supports and increases expectations in performance—be it academic, interpersonal or occupational, affecting psychological wellbeing and might manifest as depression or anxiety. It is imperative to understand the process and evolution of current manifestations and to look for underlying deficits. In this case series, the authors demonstrate the psychiatric presentation of young adults with missed ADHD diagnosis during childhood and the clinical challenge of recognizing underlying impairments associated with ADHD.

Introduction

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neuro-developmental disorder typically characterized by persistent patterns of inattention, hyperactivity, and impulsivity. ¹ Although initially conceptualized as a childhood disorder, longitudinal studies have shown that ADHD symptoms persist into adolescence and adulthood in a substantial proportion of cases.^2,3 The adult presentation often emphasizes difficulties with sustained attention, executive dysfunction, emotional dysregulation, and internal restlessness rather than overt hyperactivity.^4,5

Recognition of ADHD in older adolescents and adults remains a clinical challenge. Symptoms may overlap with mood disorders, anxiety disorders, and personality disorders, leading to frequent misdiagnosis or diagnostic overshadowing. ⁶ Structured developmental assessments and validated tools for adult populations, such as the Adult ADHD Self-Report Scale (ASRS) and the Diagnostic Interview for ADHD in Adults (DIVA-5), have improved diagnostic accuracy but still remain underutilized.^7,8 This case series highlights instances where ADHD was identified later during treatment of Axis I disorders, emphasizing the importance of longitudinal functional assessment and structured re-evaluation whenever it is required.

Brief Review of Literature

ADHD is now widely recognized as a neuro-developmental disorder with symptoms that likely persist into adolescence and adulthood. Longitudinal studies estimate that approximately 50%–60% of children with ADHD continue to experience impairing symptoms into adult life.^2,3 However, the phenotype of ADHD in older individuals differs significantly from that seen in childhood, with hyperactivity often giving way to cognitive restlessness, and inattention and executive dysfunction becoming more pronounced.^4,5

Despite the prevalence, ADHD in adults (2.5%–4.4% of the general population) remains enigmatic, with limited research and largely underdiagnosed, and only a small fraction receive a formal diagnosis if assessed for the first time during adulthood.^9,10 One reason for under-recognition is the frequent presence of comorbid psychiatric disorders, particularly anxiety disorders, depressive disorder, and substance use disorder, which may overshadow or mask the core symptoms of ADHD.^11,12 Initial assessments in most adults lead to a diagnoses of affective or anxiety disorder, delaying or probably misdirecting further assessment and intervention.^13,14

Further muddling the picture, cognitive and environmental compensations scaffold the functioning in individuals with high intellectual reserve and with structured support systems. During school years, these protective factors may temporarily buffer ADHD-related impairments, hence masking the core symptoms. ¹⁵ Thus, leading to no or minimal recognition/reporting of any impairments on assessment of developmental history. However, these compensatory scaffolds often do not hold under increased academic or occupational demands, leading to decompensation in late adolescence or early adulthood. These changes may manifest as academic failure, poor self-esteem, burnout, or emotional dysregulation, which are often misinterpreted as primary mood or personality disorders.^16,17

Emotional dysregulation, while not included in current diagnostic criteria, is recognized as a core feature of adult ADHD. It contributes to significant distress and leads to manifestation of internalizing disorders, interpersonal conflict, and hence functional impairment.^18,19 Additionally, personality traits associated with Cluster C are often observed in adults with undiagnosed ADHD and may develop as a result of long-reinforced maladaptive coping mechanisms to manage internal chaos and perceived inefficiency mediated by chronic stress. ¹⁷

More age-appropriate tools, such as the ASRS and the DIVA-5, have improved the diagnosis in the adult population, especially when used in the context of detailed clinical assessments with detailed developmental history and collateral accounts.^7,8 Clinical guidelines from NICE and other expert guidelines recommend multimodal management strategies combining pharmacological interventions with cognitive-behavioral and psycho-educational interventions targeting executive function deficits in adults with ADHD. ²⁰

Together, the literature supports a developmental framework for understanding ADHD across the lifespan, with an understanding of various cross-sectional presentations at different age groups. It also emphasizes the importance of re-evaluation in cases of partial treatment response or persistent functional impairment, especially in high-functioning youth from reasonably supportive environments. In this background, this case series intends to describe and discuss the presentation of ADHD in young adults.

Case 1

A 19-year-old male presented to the psychiatry outpatient department with complaints of low mood, academic decline, overthinking, and difficulty managing exam-related stress. Early childhood development was apparently normal, with no developmental delays. He had consistently excelled in academics, scoring above 95% throughout school. Teachers often described him as bright but at times distractible or inconsistent in completing his homework. These issues were never highlighted nor paid specific attention to, due to his strong academic record.

He had experienced two to three episodes of low mood, negative thoughts, and reduced interaction over the past few years, each of them remitting within a month or two without any formal intervention. The current episode began shortly before his competitive examination, wherein he perceived low motivation, irritability, fatigue, difficulty concentrating and emotional withdrawal. He spent more time on his phone as a distraction to manage his distress. There was no history of substance use or any risk behaviors. Family history was not significant, except, anxious traits in the mother and who was over-concerned, often micromanaging his academic schedule and sleep, when he was distressed.

Detailed clinical evaluation did not reveal any psychotic or manic symptoms. His affect was restricted, with intact insight. A DSM-5 provisional diagnosis of Recurrent Depressive Disorder (RDD), currently moderate depressive episode without psychotic symptoms and Cluster C personality traits, was made. Treatment was initiated with bupropion and relaxation training (Jacobson’s progressive Muscular Relaxation [JPMR]). Cognitive assessment revealed a superior intellectual functioning (Intelligence Quotient [IQ] score of 135 on the Wechsler Adult Intelligence Scale). Over a period of one month, he reported partial improvement in mood symptoms, but concerns remained about persistent executive function difficulties (e.g., difficulty in planning and organizing his study schedule, poor time management, problem with sustained focus and attention). He did not return for follow-up appointments and was lost to follow-up for over a year.

He returned for follow-up after about 18 months with similar complaints of academic underperformance and mental fatigue. He reported difficulties in organizing his day, completing assignments, and concentrating, despite improved mood in the period in between. The impact on self- esteem was significant. A structured re-evaluation showed longstanding issues with attention, disorganization, procrastination, and emotional disturbances, which were never considered problematic enough to seek help due to the perception of being able to function well, for which the common metric was academic success. The Adult ASRS was administered, which showed high scores on inattention. Additionally, exploration for childhood symptoms and/or impairments due to ADHD was explored from parents, and he met criteria for ADHD retrospectively, too. He expressed relief when the diagnosis and features of ADHD were discussed, saying it explained his long-term difficulties better than prior labels.

He was diagnosed with ADHD, predominantly inattentive presentation. Psycho-education regarding ADHD was done, pharmacotherapy (Atomoxetine) was initiated & gradually optimized, and strategies were discussed to reduce digital distractions, using planners and to self-monitor with measurable task milestones. At two-month follow-up, he reported improved time awareness, reduced guilt about procrastination, better mood and lesser irritability. The case illustrates how high-functioning adolescents may internalize ADHD-related impairments as failure or anxiety traits unless specifically screened and reframed.

Case 2

A 19-year-old male presented to the psychiatry outpatient department during his preparation for a national level entrance examination for engineering (in India). He complained of difficulty in concentration, fatigue, loss of appetite, and disturbed sleep, gradually worsening over the past four to five months. His family described him as increasingly withdrawn, losing interest in activities for the same duration. Birth history was uneventful, and developmental milestones were attained appropriately for age. He had always been an academically good student, with academic identity reinforced by parental and teacher praise. He was also active in cultural events and quizzes during school.

During the COVID-19 lockdown, his academic routine was disturbed. Due to stress from the pending syllabus and poor sleep, he skipped the above mentioned examination He joined a BSc Computer Sciences course, which he did not find stimulating & satisfying enough. He quit the course and re-joined coaching in late 2020. He began experiencing fatigue, difficulty in concentration, low energy, and a lack of interest in initiating any task. His sleep was irregular, and exam postponements during the lockdowns further disturbed his routine. Patient described his mother as anxious, over-involved, and frequently checking in on his routines.

He was diagnosed with a moderate depressive episode without psychotic symptoms and anankastic traits. He was started on Cap. Fluoxetine 10 mg and behavioral activation. Over the next two months, mood improved marginally, but poor concentration and overthinking persisted.

Four months later, he came for a follow-up, had looked up his symptoms online and taken a screening questionnaire, which suggested ADHD. He reported difficulty initiating even simple tasks, frequent forgetfulness, and a mental restlessness that did not align with classical depression.

A provisional diagnosis of generalized anxiety disorder with anxious-avoidant personality traits was considered with a plan for detailed reassessment for ADHD due to the presence of persistent inattention and difficulty in concentration, restlessness and overthinking. On reassessment, a detailed clinical history and early developmental history suggested chronic executive dysfunction and resultant stress with periods of functional compensation, which was corroborated by the mother, too. Adult ASRS assessment suggested inattentive features of ADHD. The presentation overall aligned with ADHD, predominantly inattentive presentation, likely longstanding and only partially compensated by a structured environment and motivation. His anankastic traits were reinterpreted as coping adaptations developed in the face of chronic internal stress.

He was diagnosed with ADHD and started on Atomoxetine 10 mg per day, which was gradually up-titrated. Cap fluoxetine was discontinued. Psycho-education focused on ADHD’s impact on anxiety and avoidance. He expressed relief at the re-conceptualization and began structuring his day, including environmental modifications like screen use restrictions and scheduled breaks. At the two-month follow-up, mild improvements in focus and emotional burnout were noted, and he reported reduced guilt about perceived laziness.

Case 3

A 30-year-old male presented to the psychiatry outpatient department with complaints of longstanding mood fluctuations, irritability, sleep disturbances, and a preoccupation that he was suffering from an undiagnosed mental illness. He described himself as someone who had always functioned below his perceived potential and attributed his academic and professional struggles to a pattern of absent-mindedness and inefficiency. His birth history was uneventful, and he had no delay in developmental milestones. He had performed well in school and wanted to secure a seat in a tier 1 engineering college (in India), but reported that his absent-mindedness stopped him from doing well.

Following this, he completed an undergraduate degree with satisfactory academic performance and held a job for a brief period. He later started his own start-up, which initially grew steadily. However, once he planned on scaling up, the responsibilities increased, and the workload required sustained effort, when he reported experiencing burnout and decreased motivation. He eventually quit the business, feeling overwhelmed. Then, he set a goal to pursue an MSc in Physics at a premier engineering and technology institute, preparation for which put him under stress again. He reported irritability, anger outbursts, disturbed sleep and restlessness, accompanied by a sense of underachievement throughout his academic life.

A provisional diagnosis of moderate depressive episode was considered during the first visit, and started on sertraline 50 mg per day, increased to 100 mg/day and Clonazepam 0.5 mg/day in divided doses. A detailed assessment was done, when a diagnosis of generalized anxiety disorder (GAD) as per DSM-5 was made with anxious-avoidant personality traits. Despite mood improvements with sertraline, he continued to report difficulty concentrating and managing tasks independently.

Due to continuing perception of stress and executive dysfunction (difficulty concentrating, inability to persist in times of increased demand, planning and execution of tasks), a focused reassessment for ADHD was undertaken, which, in addition to assessing current symptoms and impairments, also included gathering detailed early childhood history for ADHD from parents. The current score on the Wender Utah Rating Scale for ADHD was 66 (cut-off score is 46). The assessment revealed a longstanding pattern of inattention, disorganization, emotional dysregulation, and difficulty with planning and follow-through since childhood, which confirmed the diagnosis of ADHD in early childhood, too. These symptoms had been normalized as stress or response to failure/underperformance or reframed as personality traits.

The diagnosis was revised to ADHD, started on Atomoxetine (up to 50 mg/day), with sertraline tapered and stopped. Psycho-education focused on understanding ADHD as a neuro-developmental condition, reframing past academic and occupational struggles, and addressing maladaptive coping styles that had emerged over time. He responded well over the next few months, reporting improved concentration, improved mood, and better sleep. Over the two years since he was diagnosed with ADHD, he maintained regular follow-ups. He cleared the entrance examination and secured admission into an MSc Physics at a tier 1 engineering college in India. He described that his functioning was better than before. This case highlights the trajectory of undiagnosed ADHD into adulthood, particularly when misattributed to personality or affective symptoms, and the potential for functional recovery when appropriately identified and treated.

Discussion

This case series highlights the delayed identification of ADHD across a range of developmental stages—from late adolescence to adulthood. All three individuals initially presented with internalizing symptoms, executive dysfunction, or affective distress. Each was first diagnosed with Axis I disorders, such as depressive disorder or anxiety disorder, with ADHD being considered following partial treatment response, longitudinal course review, or self-initiated screening. The challenges of diagnosing ADHD in adults when missed in childhood can be varied. For instance, the focus of clinical evaluation is the presenting complaints, and not considering these as arising out of impairments related to ADHD. Second, the ignorance of adults presenting with impairments due to ADHD. And to some extent, the lack of expertise and skills required to elicit ADHD symptoms in adults. In the first and third cases, non-response or partial response to the presenting complaints necessitated further exploration in lines of ADHD, while the second case highlights how individuals struggle to find explanations for their difficulties and look for answers online. Despite variation in age and occupational functioning, several core themes were consistently observed across the cases.

A prominent commonality was the presence of high intellectual functioning and relatively stable familial environments. None of the cases had early disruptive behavior or learning concerns that would typically trigger developmental evaluation during childhood. Instead, ADHD symptoms manifested subtly as inefficiency, distractibility, internal restlessness, and planning difficulties—often normalized or reframed by caregivers, educators, or the individuals themselves as personality traits, anxiety, or low motivation. This phenomenon, previously described in the literature as “scaffolded functioning,” ¹⁵ appears to delay diagnosis until academic structures are removed or compensatory strategies fail under increasing environmental demands.

Academic transitions served as major stress points in all cases. In Case 1 and Case 2, the transition to high-stakes entrance exams and higher education environments exposed longstanding but unaddressed executive deficits, resulting in emotional dysregulation and academic decline. In Case 3, a significant transition occurred later in life, during the shift from business ownership to re-entry into academic preparation. This case also demonstrated how untreated ADHD may result in episodic burnout, professional dissatisfaction, and chronic underachievement, despite adequate opportunities and prior success. Importantly, the adult case involved self-initiated help-seeking following years of misdiagnosis, a trajectory noted in the literature on adult ADHD presentations with secondary mood and anxiety complaints.^6,16

All three individuals exhibited traits from the anxious-avoidant or anankastic personality domains, and two had previously been labeled with Cluster C traits. This reinforces findings that adults with undiagnosed ADHD may develop maladaptive coping mechanisms—such as perfectionism, excessive control, or avoidance—to manage internal chaos. ¹⁷ These traits, while sometimes functional, are often pathologized in isolation, leading to misdiagnosis or partial treatment responses. When viewed dimensionally, they appear to be downstream adaptations to longstanding executive inefficiencies and chronic cognitive overload.

Another shared theme was emotional dysregulation and self-critical internal dialogue. Each patient reported guilt over procrastination, feeling “lazy” or “not living up to potential,” particularly when academic performance declined. These internal narratives often fueled distress and led to a cycle of functional avoidance, de-moralization, and worsening mood symptoms—consistent with literature on ADHD-related affective dysregulation and secondary depression.^9,18,19 Reframing these experiences within a neuro-developmental model, supported by psycho-education and structured intervention, appeared to reduce self-blame and improve treatment engagement.

The role of structured screening was critical in all three cases. In Case 1 and Case 2, diagnosis was preceded by administration of the Adult ASRS, and in Case 3, the Wender Utah Rating Scale. Notably, in two cases, the diagnostic reconsideration was initiated by the individuals themselves after accessing resources online—a trend increasingly reported in adult ADHD literature. ¹⁴ This reflects the growing awareness of adult ADHD and the need for clinicians to validate and investigate concerns from patients with structured assessment.

From a management standpoint, pharmacological interventions (fluoxetine, Atomoxetine, sertraline) were individualized and generally well-tolerated, with adjunct psycho-education and behavioral strategies targeting routine-building, self-monitoring, distraction control, and task management. At follow-up, all three cases showed improvement in self-regulation, academic or occupational engagement, and insight. Importantly, the longest followed-up of the three, Case 3, showed significant functional improvement over a 2.5-year follow-up period, emphasizing that even in adulthood, ADHD diagnosis and targeted treatment can lead to personal and vocational betterment.

Another important factor is the male predominance in this case series. Although ADHD is more common in boys during childhood, the gender differences are minimal during adulthood. Male bias in diagnostic criteria has shaped the way ADHD is seen. Historically, core symptom descriptions were derived initially from studies of hyperactive boys, with emphasis on disruptive behaviors. Adult women, however, often present differently with less overt history of hyperactivity and more internalized features, such as inattention, chronic disorganization, and emotional dysregulation. Societal expectations and gender roles, like being “organized” or “composed”—further push women to mask or compensate for these symptoms. As a result, many women are underdiagnosed or misdiagnosed with anxiety or depression. This gendered invisibility delays recognition and treatment in females through adulthood.^21–23

Summary & Conclusion

Overall, this case series highlights the need for a developmental and dimensional perspective in evaluating youth and adults with chronic academic or emotional struggles. In high-functioning individuals, the absence of early behavioral presentations should not exclude the possibility of ADHD, especially when symptoms of executive dysfunction, emotional burnout, or personality-related distress persist despite appropriate treatment for mood or anxiety disorders. Clinicians should be open to revisiting the diagnoses whenever faced with a lack of functional improvement, especially in light of patient narratives and evolving awareness. Early recognition and appropriate intervention may prevent functional impairment in the long term and improve psychosocial outcomes.