When ADHD Goes Unnoticed: The Hidden Impact of Undiagnosed ADHD on Confidence and Mental Health
By Dr Bradley Powell, Clinical Psychologist
Why recognising ADHD early matters
Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most widely discussed neurodevelopmental conditions today. Yet despite growing awareness, many children and adults in the UK still go undiagnosed or only receive an ADHD diagnosis later in life.
When ADHD is not recognised early, children often internalise the belief that they are lazy, careless, or simply “not good enough.” This misunderstanding can quietly erode self-esteem and confidence, with effects that often extend into adulthood.
How ADHD symptoms are missed in children and teenagers
ADHD does not always fit the common stereotype of a “hyperactive boy who can’t sit still.” Many children, particularly girls, display inattentive ADHD symptoms such as:
Daydreaming
Disorganisation
Forgetfulness
Quiet distractibility
Because these traits are less disruptive, they are often misinterpreted as immaturity or lack of effort rather than signs of ADHD.
Children with high intelligence may also mask ADHD by working twice as hard to keep up at school. To teachers and parents, they may appear capable, but beneath the surface, they are battling to sustain focus and organisation. This can delay an ADHD diagnosis for years.
The impact of late or missed ADHD diagnosis
When ADHD is overlooked, difficulties are often mistaken for behavioural problems or personal flaws. Over time, this can lead to significant emotional and relational challenges:
Low self-esteem - being repeatedly told to “try harder” or that you are “lazy” despite genuine effort creates a deep sense of inadequacy.
Anxiety and depression - ongoing struggles to keep up may be internalised as personal failure.
Family conflict - misunderstandings can create tension when difficulties are viewed as laziness or defiance.
Risky coping strategies - some teenagers turn to substances such as cannabis to manage focus or calm racing thoughts.
Adult burnout - many adults only discover they have ADHD after years of overworking to keep up, often at the expense of their wellbeing.
Even after an ADHD diagnosis is made, the emotional toll of years of misunderstanding may persist. Feelings of shame, frustration, or “not being good enough” often require specialist therapy to address.
ADHD is more than a diagnosis
It is important to remember that ADHD is not simply about challenges, as it also brings strengths. Many people with ADHD demonstrate creativity, energy, problem-solving skills and determination. With accurate diagnosis, understanding, and the right therapeutic strategies, individuals with ADHD can thrive in school, work, and relationships.
Private ADHD assessments and therapy in London
At Regal Private Therapy Practice, based in the Harley Street medical district, we provide specialist private ADHD assessments for children, teenagers, and adults. Our neuroaffirmative approach ensures we not only identify areas of difficulty but also celebrate the strengths associated with ADHD.
I also work as a Clinical Psychologist at Schoen Clinic Chelsea, where I contribute to their dedicated ADHD service.
An accurate, compassionate assessment is the first step in reframing experiences and setting up the right support.
ADHD therapy and support
Following assessment, we offer tailored therapy and coaching, depending on each person’s needs:
CBT and ADHD coaching - practical strategies to improve focus, manage time, boost confidence and address co-occurring mental health challenges.
Family support - helping parents and carers understand ADHD and adapt the home environment to reduce conflict.
Substance use - supporting people who may be self-medicating with substances to develop healthier coping strategies.
Adult therapy - helping those recently diagnosed to process feelings of shame, build resilience, and strengthen self-acceptance.
This ensures that assessment is not the end point, but the beginning of meaningful support, enabling individuals to manage challenges while embracing their strengths.
Changing the story of ADHD
The cost of missed or late ADHD diagnosis is not just about forgotten homework or missed deadlines. It is about the quiet erosion of self-worth that comes from years of feeling different without knowing why.
By recognising ADHD early, and by providing accurate assessment and therapy, we can help children, teenagers, and adults reframe their experiences and see themselves not as flawed, but as capable, resilient and full of potential.
Book a private ADHD assessment in London
If you or your child are struggling with difficulties that may be linked to ADHD, professional support is available.
Contact Regal Private Therapy Practice today to arrange a private ADHD assessment or therapy session.
With the right assessment, therapy, and strategies, it is possible to move beyond self-doubt and build a more confident, fulfilling life.
📍 Regal Private Therapy Practice - Harley Street Medical District & Chelsea
📍 Self-funding and self-referrals welcome
About the author
Dr Bradley Powell is an award-winning Clinical Psychologist and Co-Founder of Regal Private Therapy Practice. He is also the Clinical Lead at Nos Curare, a specialist private neurodevelopmental practice in the Harley Street Medical District, as well as his role at the Schoen Clinic Chelsea, where he works with children, adolescents, and adults.
He specialises in treating anxiety, depression, low self-esteem and neurodevelopmental conditions such as autism and ADHD. Combining evidence-based therapies with a warm, personalised approach, Dr Powell helps individuals better understand themselves, overcome challenges and build long-term resilience.
