When ADHD Goes Undiagnosed in Adulthood

Attention deficit/hyperactivity disorder (ADHD) has been conceptualised as a neurodevelopmental disorder characterised by persistent patterns of inattention, hyperactivity, and/or impulsivity that interfere with functioning or development (APA, 2013). It used to be thought of as a childhood disorder, although now it is believed to be more complex and can persist well into adulthood.

Moreover, research shows that 30-70% of individuals with ADHD continue to experience symptoms into adulthood (Faraone et al., 2006). The symptoms exhibited by adults with ADHD differ and are more complex from the symptoms in childhood and adolescence, leading to misinterpretation and misattribution of these symptoms. The nature of adult ADHD is such that it is compounded with other co-occurring disorders (eg, bipolar disorder, anxiety disorder, etc.). These co-occurring disorders are the ones that get treated by the clinicians rather than the root cause, adult ADHD.

This results in countless adults who struggle daily with challenges that they don’t understand – at work, in relationships, and with their self-esteem. Studies have shown that without proper recognition and diagnosis, adults with ADHD face career roadblocks, strained relationships and even emotional turmoil (Miller et al., 2014). The nature of adult ADHD is such that it presents itself differently, which makes it especially challenging. The hyperactive child may become: the grown-up who finds it difficult to concentrate in meetings, the constant procrastinator who fails to meet deadlines or even the “spacey” friend who consistently forgets plans. 

Read More: Flow States Vs. Hyperfocus: How ADHD Challenges Traditional Motivation Theories 

Misinterpretation of Symptoms 

Numerous maladaptive and dysfunctional behaviours like constant fidgeting, strong emotional reactions, uncontrollable daydreaming, and restless nights are seen as symptoms of ADHD (Asherson et al., 2016). However, the fact is that these symptoms are mislabeled as personality defects or other mental health issues, and that is one of the most harmful effects of undiagnosed ADHD. 

• Chronic procrastination: People with adult ADHD are motivated but struggle to start and even finish tasks (Barkley, 2010). 
• Disorganisation: Ineffective time management, missing deadlines, or losing things frequently are examples of a few disorganisation symptoms faced by people (Brown, 2005). Even routine chores like scheduling appointments and paying bills can feel too much to handle for them.
• Impulsivity: They frequently keep making snap judgments about money, relationships, or even career changes (Kessler et al., 2006). Such adults frequently have a persistent mental clutter or an inability to relax, which makes concentration extremely taxing, in contrast to childhood hyperactivity. 
• Emotional dysregulation: Intense mood swings and hypersensitivity to criticism (Barkley, 2012), having problems calming down when they are mad, overreacting to relatively small stresses, etc., are a few examples of how these adults have a problem in effectively regulating their feelings and emotions. 
• Indecisiveness: Studies have also shown that adults with ADHD often experience indecision and various other decision-making-related problems (Schulze et al., 2021; Cherry, 2023). These are also related to the same executive functioning impairments that lead to many other symptoms of adult ADHD, like planning, organising, etc. 

Read More: How ADHD Affects Emotional Regulation

Friends and family may mistake their reactions as being too emotional, quick-tempered, or hostile (Cherry, 2023). Even the person themselves with undiagnosed ADHD experiencing these intense and upsetting thoughts, behaviours and emotions may not understand why they can’t seem to moderate these. Many adults label themselves as “lazy” or “irresponsible,” leading to chronic low self-esteem (Knouse et al., 2013), and they even start blaming themselves (CHADD, 2022). 

Read More: Productivity Tips for ADHDers 

Functional and Psychosocial Difficulties 

1. Workplace Performance 

Due to symptoms that people with ADHD experience, they might find it difficult to cope and adapt to everyday tasks in their workplace. Attentional difficulties, chronic disorganisation, restlessness, etc, can lead to missed deadlines and poor work quality. Studies indicate that adults with untreated ADHD are three times more likely to be unemployed (Biederman et al., 2006). It is also seen that they are more likely to change jobs frequently due to boredom or frustration (Kessler et al., 2006) and are even at higher risk of underemployment despite high intelligence (Barkley, 2010). 

Read More: ADHD and Workplace Challenges

2. Difficulties in Maintaining Relationships 

Symptoms of ADHD, like poor listening skills, being hyperactive and getting easily frustrated, can lead to problems and complications not only with colleagues but family, friends and partners as well (Ginsberg, 2014). Undiagnosed ADHD can strain relationships since people exhibit certain symptoms without the knowledge that they even exist and how to properly manage them. Few of these symptoms are: forgetfulness (missed appointments, anniversaries), impulsive reactions leading to conflicts (Eakin et al., 2004) and even perceived unreliability by partners (Robin, 2002).  Studies have also shown that marital dissatisfaction is higher in couples where one partner has undiagnosed ADHD (Robin & Payson, 2002). 

How Undiagnosed ADHD Affects Daily Life and Health 

Adults with undiagnosed ADHD often face real-world challenges and consequences beyond the symptoms of forgetfulness or disorganisation. Research shows these difficulties can impact safety, health, and healthcare costs in significant ways. 

1. Increased Risks on the Road 

Studies have time and again shown that ADHD affects driving abilities (Barkley, 2002). Adults with ADHD tend to get more traffic tickets and have more car accidents and even struggle with distracted driving, speeding, and impulsive decisions behind the wheel. They also have nearly 4 times higher risk of serious crashes, according to some studies. Such risks arise from ADHD symptoms like impulsivity, inattention, and trouble focusing for long periods – all crucial skills for safe driving. 

2. Higher Healthcare Needs 

The impact on physical health is equally concerning. A study by Kirino et al. (2015 found that adults with ADHD visited doctors 10 times more often, went to emergency rooms 3 times as frequently and were hospitalised 3 times more often. These shocking numbers likely come from several factors like accident-prone behaviours (like car crashes or injuries from impulsive actions), missed medications or forgotten doctor’s appointments due to ADHD symptoms and co-existing conditions that often accompany ADHD, as anxiety or mood disorders. 

Read More: Understanding the Link Between ADHD and Alcohol Use

Substance Use and Addiction Risks in Adults with ADHD 

Adults with untreated ADHD face significantly higher risks for substance abuse and addictive behaviours. Research shows they’re 2-3 times more likely to develop alcohol use disorders (Wilens et al., 2007). They are more prone to nicotine dependence (Kessler et al., 2006) and are at a greater risk for drug use and prescription medication misuse (Zulauf et al., 2014). 

1. Co-occurring conditions with Adult ADHD 

Adult ADHD is made especially challenging by how often the disorder gets mistaken for and even buried under other mental health conditions. Chronic procrastination might be labelled as depression, and even emotional outbursts could be seen as symptoms of anxiety. Moreover, symptoms of anxiety, depression and other mood disorders frequently overlap with ADHD and create a storm of symptoms that are often treated separately by clinicians while missing the root cause (Asherson,2016). Even worse, over time, undiagnosed ADHD can lead to worsening of these co-occurring conditions and these untreated symptoms fuel shame, stress and dysfunction. 

The Power of Recognition and Hope 

Living with undiagnosed ADHD in adulthood might feel like you are trying to find your way out of a maze blindfolded. But the debilitating symptoms one might face aren’t personal failures but part of a more complex underlying condition. The good news- Recognition empowers change. Proper symptom recognition and diagnosis isn’t just a label but an answer that paves way for self-compassion, targeted strategies, rebuilding relationships and prevention of further mental health struggles. While this journey may not seem easy, the growing research and attention to adult ADHD are paving the way for proper diagnosis and treatment. If this resonates with you, try connecting with a professional. The first step can change everything. 

Frequently Asked Questions

1. Can adults develop ADHD, or is it only a childhood condition? 

ADHD is a lifelong neurodevelopmental disorder—it is not something that you just grow out of. While symptoms begin in childhood, many adults remain undiagnosed until later in life when responsibilities (careers, parenting, etc.) make challenges more noticeable (Faraone et al., 2006). 

2. I was never hyperactive—could I still have ADHD? 

Absolutely. Many adults, especially women, primarily struggle with inattention (not hyperactivity). Symptoms like chronic disorganisation, forgetfulness, or emotional sensitivity may dominate (Parikh et al., 2024). 

3. How is adult ADHD different from anxiety or depression? 

• ADHD: Wanting to focus but being unable to start tasks 
• Anxiety: Overwhelming worry about outcomes 
• Depression: Lack of motivation altogether 
• ADHD often coexists with these conditions but requires distinct treatment (Asherson et al., 2016).

4. “I procrastinate all the time—does that mean I have ADHD?” 

Not necessarily. ADHD-related procrastination is extreme and persistent, often paired with:

• Time blindness is difficulty in perceiving and managing time. (“I’ll do it later” turns into weeks) 
• Shame cycles despite genuine effort to change (Barkley, 2010) 

5. Where can I get tested? 

Start with: 

• A psychologist specialising in adult ADHD 
• Online screening tools (e.g., ASRS) 
• Rule-outs for thyroid issues/sleep disorders (CHADD, 2022) 

References +

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