“Going Through Life on Hard Mode”—The Experience of Late Diagnosis of Autism and/or ADHD: A Qualitative Study

Abstract

Background:

In the United Kingdom, more than 2.5 million adults with undiagnosed neurodevelopmental conditions, such as autism and attention-deficit/hyperactivity disorder (ADHD), can face difficulties accessing diagnosis and support. Our qualitative study explores people’s experiences of receiving a diagnosis in adulthood and its impact on their lives.

Methods:

We conducted semi-structured interviews with seven health care professionals and 13 late-diagnosed adults (5 autistic, 5 with ADHD, and 3 with dual diagnoses) using reflexive thematic analysis.

Results:

We developed five themes from the analysis representing the journey and factors influencing participants’ experiences of receiving a late diagnosis: (1) the key role of relationships and mental well-being; (2) the wider impact on well-being and lifelong mental health; (3) understanding—the answer to postdiagnosis changes; (4) the flip side of diagnosis—the burden of a label; and (5) are you ready—the importance of timing.

Conclusion:

Our study demonstrates the multiple impacts a lack of diagnosis has and the many benefits experienced from receiving one. Although a lack of diagnosis can at times have some negative effects, the importance of understanding and the wider impacts on relationships and mental well-being are discussed. Primarily, the emerging concept of being ready and the importance of the right timing highlight an important nuance in the diagnosis journey.

Community Brief

Why is this an important issue?

In the United Kingdom, more than 2.5 million adults with undiagnosed neurodevelopmental conditions such as autism and ADHD often struggle to access diagnosis and support.

What was the purpose of this study?

This study aimed to explore the experiences of adults receiving a diagnosis of autism or ADHD later in life and how the lack of diagnosis affected them.

What did the researchers do?

The research involved interviews with 7 health care professionals and 13 late-diagnosed adults (5 with autism, 5 with ADHD, and 3 with both conditions). We conducted these interviews over Teams and included representations from different countries, conditions, and genders to ensure we represented a wide range of experiences.

What were the results of the study?

Through the analysis, the following five themes were developed from the analysis representing the journey and factors influencing the experiences of receiving a late diagnosis: (1) the key role of relationships and mental well-being; (2) the wider impact on well-being and lifelong mental health; (3) understanding—the answer to postdiagnosis changes; (4) the flip side of diagnosis—the burden of a label; and (5) are you ready—the importance of timing.

First, the study highlights the crucial role of relationships and mental well-being in this process. Understanding emerges as an important factor for individuals in navigating postdiagnosis changes. However, the study also sheds light on the flip side of diagnosis—the burden of carrying a label. Finally, the importance of timing was also another significant theme. The study suggests that being ready for the diagnosis and the right timing play a crucial role in the overall journey. This study emphasizes the nuanced impact of the lack of diagnosis and the various benefits that come with receiving one. Although there are instances of negative impacts and despite the challenges, the study emphasizes the positive impacts of diagnosis, emphasizing the need for a comprehensive understanding of the individual’s experiences and the broader context of relationships and mental health.

What do these findings add to what was already known?

This study adds a more comprehensive view of adults’ experiences, which have not been widely explored in research so far, in terms of the impacts, both negatives and positives, of growing up with autism or ADHD and not knowing.

What are potential weaknesses in the study?

The study would have benefited from having the voice of close friends or family members too as they might have been able to reflect in a different way on any changes the diagnosis brought.

How will these findings help autistic adults now or in the future?

These findings reinforce the benefits that can come with early diagnosis, through understanding, finding a community, and better mental health. The study also highlights the potential drawbacks of this and can help autistic adults, as well as health care professionals, understand the process of diagnosis and its potential impact (negative or positive). It can help autistic adults prepare themselves for the diagnosis process by further understanding what it might mean and how it would impact them, giving them more information.

Background

Currently, in the United Kingdom, it is estimated that more than 2.5 million adults with neurodevelopmental conditions have not received a diagnosis^1,2 and therefore struggle to access support. ³ The most common neurodevelopmental conditions, attention-deficit/hyperactivity disorder (ADHD) and autism, affect 5% and 1% of children and adults in the United Kingdom, respectively—on average one child per classroom.^4–6

Autism is a lifelong condition resulting in differences in social and communication style, difficulties adapting to unexpected change, restricted interests, and sensory processing differences. ⁷ ADHD is categorized by symptoms of impulsivity, hyperactivity, and inattention leading to considerable daily impairment.^8,9 Individuals with autism/ADHD and their families have reported many impacts of these conditions such as significant academic underachievement and educational problems,^10–12 increased prevalence of depression and anxiety,^13,14 higher rates of offending behavior and imprisonment,^15–17 divorce, ¹⁸ driving accidents,^19–21 unemployment,^13,22,23 suicidal thoughts and behaviors,^24,25 and other mental health issues.^26,27 Studies have shown that adults with undiagnosed autism/ADHD are more likely to have educational problems, depression, and anxiety; commit crimes; and abuse substances. ²⁸ In most health care systems, a formal clinical diagnosis is necessary to access support services; therefore, these poor outcomes could be reduced with earlier identification.^29–31

Although autism and ADHD are developmental conditions, many autistic people and/or people with ADHD (henceforth autism/ADHD) have been missed in childhood and only receive a diagnosis in adulthood. ³² In addition, it is estimated that millions of adults with autism/ADHD are currently undiagnosed in the United Kingdom,^33–35 and this issue prevails around the world. In Denmark, for instance, more than half of the children surveyed in a national birth cohort who reported ADHD behavior at age 7 were not diagnosed at follow-up many years later. ³⁶ Autism and ADHD often overlap with 38.5%–59% of individuals having both conditions,^37,38 sharing high genetic heritability and impaired social and executive functioning. ³⁹ Both conditions are widely underdiagnosed^2,40,41 and carry significant stigma.^42–44 In addition, the diagnostic process and care pathways for autism/ADHD are often very similar. ⁴⁵ These shared experiences highlight the importance of exploring overlapping experiences across these two conditions.

Few qualitative studies have explored the experience of receiving a late diagnosis of autism/ADHD in adulthood. Studies have highlighted the negative impacts of lack of diagnosis, the process of acceptance, and the feeling of being different.^46–48 A qualitative study exploring the experiences of late-diagnosed autistic men highlighted the negative impact that late diagnosis had on their psychological well-being and the benefits of receiving an explanation for long-standing difficulties. ⁴⁶ Another qualitative study of late-diagnosed autistic women showed the impact of limited understanding of others, the stigmas and assumptions around autism, and the process of acceptance. ⁴⁷ Similarly, women report high levels of masking autistic characteristics, vulnerability, and specific difficulties with gender-centered demands. ⁴⁹ Gellini and Marczak ⁴⁸ describe the experience of late diagnosis of autism as “feeling like an alien,” not understanding why you don’t fit in as well as a sense of liberation from being able to be yourself postdiagnosis.

With regard to ADHD, Matheson et al. ⁵⁰ describe a persistent sense of failure and missed potential from living with the impact of ADHD impairment. It led to an accumulated psychosocial burden, especially among those diagnosed from late adolescence onward, and positive adjustment was facilitated by a younger age at diagnosis. In addition, delayed diagnosis has been shown to cause suffering and dysfunction, by adding unnecessary struggles and highlighting the potential of a better life, what could have been if ADHD had been recognized earlier.^51–53 The positives of receiving a diagnosis was the most widely shared experience, by providing self-knowledge, a sense of belonging, and increased value. Finally, Aoki et al. ⁵⁴ described the relief and acceptance that the diagnosis brings.

The experience of adult diagnostic processes of autism/ADHD is very similar across the two conditions ³⁹ and reflects a commonality in the impact that undiagnosed neurodevelopmental conditions have. Although previous studies have explored these impacts in specific contexts such as gender experiences, this study wanted to investigate these impacts through a broader lens, regardless of condition, gender, country, and other factors. To gain further understanding of the factors intertwined with late diagnosis of autism/ADHD, our qualitative study explores people’s experiences of receiving a diagnosis in adulthood and the impacts this had on their lives.

Methods

Study design

Our study investigates the following question: What are the experiences of adults receiving a late diagnosis of autism/ADHD? The lead investigator (B.F.) conducted the interviews over the course of a month in August 2023.

Participants

We recruited 20 participants from two different groups as follows: (1) health care professionals who specialized in autism/ADHD diagnosis (n = 7) and (2) and people who had been diagnosed with autism and/or ADHD in adulthood (n = 13). Participants originated from across the United Kingdom (n = 15) and other countries (two from the United States, one from France, one from Germany, and one from Australia). We selected participants through our research database and contacts to give a representative sample in each group. Participants with autism/ADHD were selected from our database to represent a range of genders, conditions, ages, and time since diagnosis, ⁵⁵ whereas health care professionals were selected from our personal contacts to represent adult and children services for both conditions. Our database comprises more than 300 adults diagnosed with autism/ADHD, recruited throughout different research projects and who wanted to take part in future research. Owing to ongoing issues with fake participants taking part in online studies, ⁵⁶ multiple checks had been made to ensure that the participants were genuine. We interviewed participants in no specific order to limit biases from specific groups and offered all participants a £20 voucher for their time.

Health care professionals

We interviewed three male and four female health care professionals (mean age: 49 years, range: 41–55). Four participants worked within public health care adult services and dealt with adult diagnoses of autism/ADHD (one in Germany and three within the UK National Healthcare System [NHS]). Two participants worked with children in NHS diagnosis settings of ADHD, whereas one participant worked privately and diagnosed children and adults with autism/ADHD.

Late-diagnosed adults with autism/ADHD

We interviewed four male, eight female, and one non-binary adult diagnosed with autism/ADHD in adulthood (mean age: 45 years, range: 30–62). Five participants had received an autism diagnosis, five an ADHD diagnosis, and three both. Participants had to be older than 25 and have over 4 years since diagnosis to be eligible, allowing for greater insight into the impact of the diagnosis.

Advisory group

We recruited an advisory group of nine adults diagnosed with autism/ADHD in adulthood from UK-based charities and support groups. Our advisory group informed the development of the interviews and helped the research team interpret findings from our previous systematic review ²⁸ and identify risks not explored in previous research and those risks that require further investigation in our current qualitative study. The group also assisted in drafting the interview schedule, reflecting on topics covered and the language used for all the questions.

Data collection

We conducted individual semi-structured interviews to explore the risks associated with late diagnosis of autism/ADHD in adulthood. After we discussed the interview process with participants, we obtained informed consent through a secure Microsoft form filled in by the participants at the beginning of the interview. We offered participants a choice of telephone (for UK-based participants) or online interviews on Teams. We developed two interview schedules (one for health care professionals and one for adults) based on a recent systematic literature review ²⁸ and discussion with our advisory group, which included specific topics as well as more open-ended questions (Supplementary Data S1). We applied the interview schedule flexibly and reviewed this regularly with data analyzed in an iterative process. We changed or added questions as different topics emerged throughout the interviews. We also omitted certain questions depending on the participant’s experience. We took detailed notes after each interview and following each analysis step, which were included in an analysis diary. We recorded all interviews, transcribed these verbatim, and subsequently anonymized these. Our institution’s ethics committee granted ethical approval for our study (approval reference: F1440R).

Data analysis

We used reflexive thematic analysis to analyze the data. ⁵⁷ We chose this analysis method as it facilitates capturing opinions, views, and experiences and how these are interconnected. The lead researcher (B.F.) also has extensive personal experience on the topic, which would have impacted data analysis, lending itself well to the reflexive component of thematic analysis.

The lead researcher (B.F.) undertook the thematic analysis from an essentialist theoretical position with experiences understood as the participant’s reality. Analysis was data driven and carried out inductively, and themes were derived from the data, as opposed to from a preexisting theoretical framework or previous research. B.F. identified themes and subthemes using an adapted approach of Braun and Clarke’s ⁵⁷ reflexive six-stage process as follows. The analytic process began by transcribing each interview verbatim, shortly after being conducted. Following this process, the lead investigator first familiarized herself with the interviews by listening to the audio tapes and reading through the transcripts several times. Following verbatim transcription, the lead investigator took notes in a diary of her preliminary thoughts on the content of the interviews. From this close familiarization with the transcripts, preliminary codes were identified in a coding manual. After familiarization with these codes and long reflections on their meaning, they were then collated and combined to be classified into broader themes using ongoing comparative analysis both within and between transcripts. Finally, as the analysis evolved, these broader themes were reviewed and refined and generated the final themes proposed. To get a meaningful analysis, we ensured that data within each theme were coherent about each theme and subtheme as well as within the context of the overall data set. While previous literature reviews ²⁸ highlighted topics that needed to be explored, we developed the interview schedule in a way that allowed new topics to emerge inductively within the interview schedule, aiming to freely explore the participants’ experiences. Our ongoing analysis allowed for a clear definition of the final themes. A second researcher (S.C.) reviewed the resulting themes to ensure that they mapped to the original transcripts. The second researcher also confirmed that data saturation was reached and that no new themes emerged in the last few interviews. The second researcher checked the coding manual and theme extraction along with the individual coding of transcripts. Inter-rater reliability was tested on a small proportion (10%) of the transcripts’ themes and subthemes and showed a unanimous agreement in the classification of the themes. Our results were validated collectively as a team, and any discrepancies were discussed and reconciled.

Positionality statement

It is important to note that the main researcher B.F. approached the interviews from multiple standpoints: a service-user, a clinical, and a researcher standpoint. First, having received a diagnosis of ADHD as an adult, B.F. had extensive experiences with primary care from a service-user’s point of view. Second, B.F. has been facilitating service-user’ workshops for parents and adults with ADHD for the last 13 years. Finally, B.F. has been working as a neurodevelopmental researcher for the last decade. As such, she brings her own biases to this important topic, and her personal experience will have impacted the analysis as well as the questions and methods for this study. While keeping as much integrity as possible, it would be impossible to be completely objective while dealing with such a sensitive topic. B.F. had a very positive experience of receiving a diagnosis in adulthood and it is important to acknowledge the potential biases this might create. Careful consideration was given to not letting personal experiences affect data collection and minimize the impact on data analysis, and B.F. did not disclose her personal experiences to the participants during the interviews. Despite her best efforts, this sensitive topic brought a lot of high emotional responses throughout the process by hearing similar experiences or other’s struggles. Therefore, bear in mind the context and positionality of the lead researcher in the study within which the data were collected and analyzed.

Results

We generated the following five themes from our analysis: (1) the key role of relationships; (2) the wider impact on well-being and life-long mental health; (3) understanding—the answer to postdiagnosis change; (4) the flip side of diagnosis—the burden of a label; and (5) are you ready—the importance of timing. The themes represent the journey and factors that influence the experiences of receiving a late diagnosis.

Theme 1—the key role of relationships

This theme centered on the importance of relationships. In this context, the term “relationship” includes different aspects of social life, including friendships, partners, families, work colleagues, teachers, and acquaintances. Relationships seem to be at the core of many struggles and positive supports that impact work, education, and many more aspects. These nuances of the impact of relationships are discussed further below.

Prediagnosis, relationships seemed to impact everything, from school performance to employment or self-esteem. Some adults with autism/ADHD felt that because of the nature of autism/ADHD, they were an easy target for others and were sometimes taken advantage of. Their self-beliefs about what they could achieve and how they could react were constantly affected by others’ beliefs. “I thought I was a moron. I didn't finish high school. Yeah, I was just always kind of treated like I was lazy and stupid, so I assumed that was correct” (P8).

However, the support of specific relationships could also have a positive impact, supporting individuals through their struggles. The support of partners or parents can make all the difference in whether individuals retain a job, stay, and perform well at school or manage social situations. “They set up a special program […] So I actually was able to succeed in school because of that program that my mom and my teacher developed” (P5).

Postdiagnosis, adults with autism/ADHD felt that receiving a diagnosis impacted how partners, friends, or parents interacted with them. Although a couple of relatives experienced the diagnosis negatively, primarily having an explanation for their difficulties was received very positively. Families could then understand better and can put strategies and support in place such as learning not to fight, not getting offended by certain behaviors, and being more accepting of who they are. “There was a lot of conflict. There was my girls living with their father at times, really hating me. I mean, so much conflict that we had to get services involved, family services […] but I have great relationships with my daughters now, and we’re all more aware of talking about our triggers” (P14).

Many participants reported positive and negative impacts of the diagnosis on relationships. It helped some set boundaries with others and realize who was truly supportive of them. While this could create further distance from others, it was mostly felt as a benefit as they struggled less. For many, being able to understand their differences led to better communication in work, school, marriages, and peer situations. “My relationships were unhealthy, very, very unhealthy. And I would think, well, that’s the best you can get because you’re flawed, at the back of my head, that’s what I was thinking. But now I’m in a very healthy relationship” (P13).

Receiving a diagnosis allowed many adults with autism/ADHD to feel like they belonged and to find a different community. The sense of community of sharing experiences with others experiencing the same gave a new meaning to relationships. “How important community is and finding other ADHD people. Because I felt so lonely all my life, I felt so different and I just felt like I was just a failure and a weirdo […] And just finding other people that just get you […] we get each other” (P14).

Finally, advocacy was also very important, both in terms of feeling confident to advocate for themselves and also for others. Some adults with autism/ADHD became advocates for others, supporting families, creating peer communities, and championing this new-found identity and its community. “The only thing is, I'm much more advocating for the people, especially people I know that are neurodivergent and struggle to express themselves or get the treatment” (P3).

Theme 2—the wider impact on well-being and lifelong mental health

Every participant’s testimony described how their mental well-being was impacted throughout their lives, prediagnostic principally but also during and postdiagnosis. The concept of not fitting in, and being different was strongly highlighted and this could change by gaining understanding.

All participants reported mental-health difficulties postdiagnosis, including anxiety, depression, suicide ideation, self-harm, and addiction. Their sense of self was strongly impacted by existing in a world where they felt they didn’t fit in, including a lot of self-blame and self-esteem. Burnouts were often experienced, sometimes impacting their sense of safety. Adults with autism/ADHD felt that a lot of their difficulties were their fault, that they were “broken.” All participants reported difficulties in growing up feeling different and not understanding why, feeling like something was wrong and that they were not good enough, continuously impacting their self-esteem. “Just knowing that I’m not a broken version of something else that I’m exactly how I meant to be as an autistic and ADHD person. I just used to think that I’m just bad at this, I’m just bad at being a human” (P7).

I had this idea in my head that I would never get better and that I would just, end up taking my life because I couldn’t keep going because it was just too much all the time. (P11)

Receiving a diagnosis mostly impacted mental well-being positively, often bringing hope. Most adults with autism/ADHD felt better afterward, being able to understand and work around their mental health difficulties. It allowed them to validate and accept their past experiences and struggles. They felt more able to regulate and communicate their emotions, having fewer meltdowns and burnouts. While some mental health struggles were explained and lessened, some struggles were still present, but they were able to find strategies to stop them “spiraling.” The diagnosis helped them feel able to deal with day-to-day struggles and at times feel safer and more confident. “[A diagnosis] it gives it a licence, it gives it fairness, it gives it recognition. I can own it and treat it, I can understand it. Just knowing why you do those things impacts on your schema and your self-esteem” (P101—health care professional).

Theme 3—Understanding: the answer to postdiagnostic change

The key benefit of receiving a diagnosis was being able to understand why relationships are difficult, why you feel like you don’t fit in, and why things like school and education are harder for you. The concept of validation and giving a framework was widely discussed and how it allowed adults with autism/ADHD to understand their strengths and weaknesses and seek support/strategies accordingly.

The main feeling postdiagnosis was one of validation and acceptance. The diagnosis gives meaning, ownership, and a framework to work around. It highlights a framework within which adults with autism/ADHD can own their differences. It is not an excuse but an explanation of why it isn’t their fault. It increases confidence and adults reported being kinder to themselves, giving themselves more time, more breaks, or caring less about being different. “I really think that every single day my life is impacted positively by having a diagnosis and better self-understanding” (P06).

I was actually in the same gear as everyone else that’s the best way to describe it because (before) I seem to have always been stuck in first gear. (P01)

The understanding that comes with the diagnosis also allows most adults with autism/ADHD to understand both strengths and difficulties. They can assess the positives that come with their differences as well as the areas of life that they struggle more with. By understanding this, they feel better able to be who they are and navigate the complexities of living with autism/ADHD in a typical world. “It’s giving me permission to be myself more and unapologetically myself” (P07).

But just having that understanding that you do this because you have ADHD, not because you’re a failed human. (P14)

The diagnosis allows individuals to put strategies in place, as well as access support that facilitates many aspects of life. It helps them to make the right choices, make changes, and address some of the difficulties they experienced. The changes are often a learning process of what works for them, but this sense of understanding brings many benefits and changes. “All right, what’s a good solution instead of what I previously would have done would have been probably self-blame or self-shame, not coming up with a solution and just thinking I need to do better. Seeking support for sure, but seeking the right support” (P06).

Theme 4—the flip side of diagnosis, the burden of a label

This theme describes the negative aspects of receiving a diagnosis, principally around the stigmas of the labels of autism and ADHD. Other people’s reactions were mainly to blame with them expressing strong misconceptions, misrepresentations, and stigmas. Few participants also reported negative feelings such as anger and regrets, while others felt some self-doubts.

The stigmas around autism/ADHD labels were by far the most negative aspect experienced by adults with autism/ADHD. Some aspects of the labels and diagnosis were felt as deficit-focused, primarily highlighting difficulties rather than conditions with pros and cons. While some were at first uncomfortable with the diagnostic label, it was primarily other’s reaction to that label that was experienced negatively. They felt that the labels autism and ADHD carried a lot of stigmas that others judge them on. “Because when people talk about autistic people, they often talk about us in stereotypes like we’re not actual people” (P04).

So the child gets handed over year to year as Johnny with ADHD and people will have their stereotype of what that means. And potentially, it not so much self-fulfilling prophecy, but they might be looking out for those behaviours and giving them less opportunities or less chances from that point of view. (P102—health care professional)

Others’ perceptions also strongly impacted adults with autism/ADHD negatively. Misunderstandings, misconceptions, and misrepresentations around the diagnosis were often very difficult to deal with, such as having to explain yourself or not react to others’ misplaced comments or actions. Participants also reported that others would compare their conditions with others they knew or would force a conversation about autism/ADHD just because they knew you had a diagnosis. One participant was asked randomly to explain what autism was like and she responded, “I don’t know how to explain it because it’s different and it’s, you know it’s just who I am. It’s like asking me to explain to somebody how do you experience being a man?” (P07). Others just didn’t “believe” or judged the accuracy of the diagnosis. “I told her, I’ve got Asperger’s Syndrome and she said no, no, no, you’ve got far too much of a sense of humour to be autistic” (P15).

In addition, many times, these misunderstandings led to misdiagnosis as others were not able to understand these conditions fully, especially in females. For example, one participant’s ADHD was diagnosed as postpartum depression, while another picking of skin for regulating autism was diagnosed as self-harm. This lack of understanding and stigmas from others led a lot of adults to doubt their conditions. It created a lot of self-doubt and feeling like an imposter. They felt that it looked like it was an excuse for not trying as hard. “Sometimes I find it hard to accept because I get a lot of people coming up to me and going, you can’t be autistic. Am I autistic enough?” (P12).

Theme 5—are you ready? The importance of timing

The final theme highlights the importance of timing and being ready for the diagnosis. Although many adults experience the diagnosis positively, a minority do not, often because of not being ready. Age, support, and time in life as well as therapists’ preparation may affect responses to diagnosis. Adults with autism/ADHD often wonder “What could have been” with a lack of support postdiagnosis strongly reinforcing negative feelings that might arise.

A key concept highlighted primarily by health care professionals is the importance of being ready. Timing, where an adult is at, is very important to take into consideration when seeking and giving a diagnosis. If individuals are not ready, the process can lead to a lot of upset, anger, and depression. For example, understanding whether somebody is seeking the diagnosis or not is very important. Preparing the individuals for the potential outcomes is key in managing these risks. “This is one of the things that I think that ensuring that someone’s ready for an assessment is really important. NICE guidelines talk about it. I don’t think many private or NHS processes give much focus on preparing or if a child or an adult is ready to see value difference and value difference in themselves” (P105—health care professional).

Emotional readiness is also an important concept. This can be understood in where they are in their lives, in terms of environment, big life changes, and also experience and age. Younger adults seemed to accept the diagnosis very differently than older adults, the latter expressing how they felt it had come too late. Even when individuals are seeking the diagnosis, understanding the emotional place individuals are at and whether it is right for them at that point in their lives is key. “The person even wanting to go down that route, that sort of assessment route, too, because of how they might think about themselves and how other people might think about them. I think the age does make a difference” (P103—health care professional).

With this readiness comes the ability and will to change. Being able to seek support, accept the past, and alter some potential unhelpful behavior can lead to much better outcomes postdiagnosis but is directly linked to this sense of being ready to take on this label. In that sense, the diagnosis could also bring a lot of regret and anger. Only a minority of adults with autism/ADHD reported feelings of anger of what “could have been” and often felt “a sense of grief or loss in terms of it’s taken this long to get to this point and life could be different.” Especially in older age groups, adults felt like it was too late to change and that they had wasted a lot of opportunities. “One of the hardest and most awful things is realizing the wasted potential” (P08).

I just see my life as being wasted. Really. I don’t particularly enjoy it. I don’t particularly enjoy life at all. (P15)

Finally, adults with autism/ADHD had mixed feelings about whether they would like to have had the diagnosis sooner. Surprisingly, most felt that it might not have been useful. Many factors impacted this; for instance, cultural changes over the last decades mean that nowadays acceptance and understanding are much more common. However, 20–30 years ago, growing up with a label such as autism or ADHD would have not been necessarily as easy. The level of stigmas around these labels might have led to less disclosure, less self-acceptance, and potentially more struggles. “I don’t think I’d have been so open and accepting of it if it had come earlier in my life. Because female autism visibility wasn’t there. It was still very, you know, not neurodiversity affirming type things in the sense that people were like, if you’re autistic, you won’t achieve anything, you can’t do this […] I would have perhaps rejected the diagnosis rather than, you know, accept it and embody it. Whereas like now I’m very open” (P10).

Others felt that an earlier diagnosis might not have been useful in terms of the life experiences they had. By struggling through undiagnosed autism/ADHD, some felt that it allowed them to work harder, try harder, and experience things that they wouldn’t have otherwise. A diagnosis might have led to less effort, not trying as hard as they would, expecting they just couldn’t do certain things. For example, the risk-taking behavior of one participant who worked with dangerous reptiles for years would have been more controlled and might have stopped them from succeeding. “But if I could have ever changed anything, I probably wouldn’t have because of having to work that hard to get where I am now. I wouldn’t be the person I am now. If it came easy, I probably wouldn’t be trying as hard as I do now in my athletic aspects, my school aspects. So, you know, no regrets” (P5).

Discussion

Our results reflect the many ways receiving a late diagnosis impacts adults with autism/ADHD from the view of late-diagnosed adults and health care professionals. The five themes highlighted impacts on mental health and relationships, the importance of understanding through a diagnosis and label, with at times a negative side of this label, and finally, the importance of being ready for the diagnosis. The last (theme 5) demonstrates a unique facet of diagnosis that has not yet been explored in previous studies. Differences between conditions (autism/ADHD) and stakeholders (late-diagnosed adults/health care professionals) were expected. However, although each group’s data were coded separately, the similarities of their experiences meant data were combined across the groups. This suggests uniformity of the findings between the different stakeholder groups and the overlap of these two conditions.^45,58

The impact of undiagnosed autism/ADHD on mental health and relationships has been reported in previous studies.^47,50,59 Legg et al., ⁵⁹ for instance, reported how new knowledge following a diagnosis of autism facilitated change in often poor relationships and interactions. Matheson et al. ⁵⁰ showed that the persistent sense of failure and missed potential from living with the impact of unsupported ADHD impairment led to an accumulated psychosocial burden and mental health difficulties. ⁵⁰ The importance of understanding, psychoeducation, and the power held by having a diagnosis and being able to identify your struggles has also been often reported as a key component of the healing process,^22,54 primarily centered around a sense of acceptance and identity. A few of our participants described that their diagnosis allowed a deeper understanding of their mental health difficulties and why they felt like they didn’t fit in, access new communities, and help others. ⁴⁷ The concept of providing a framework was often mentioned in our interviews, which echoes findings from Lupindo et al., ⁴⁶ facilitating self-acceptance and positively impacting well-being.

The concept of not fitting in, “pretending to be normal,” ⁴⁹ or feeling “like an alien” ⁴⁸ was often discussed with all participants reporting difficulties in social interactions. Although gender was not a theme of this study, the difference between genders was often mentioned by the group of health care professionals and how the different gender presentations had different impacts. This echoes Bargiela et al.’s ⁴⁹ findings that, especially in females, gender led various professionals to miss their underlying autism and demonstrating an obvious conflict between autism and a traditional feminine identity.

The negative aspects of receiving a diagnosis were primarily centered around stigma associated with the labels of autism/ADHD. Many studies have reported the negative stigmas associated with these labels and the impact this has on access to care, ⁶⁰ education, ⁴⁴ or relationships. ⁴³ In our study, these negative experiences were mainly due to other people’s beliefs about these labels. While some participants reported an initial discomfort at times with these labels, this always changed as their understanding grew. However, the response of disclosing your diagnosis to others and their reaction can be negative and upsetting. Similar results were found where many benefits of a diagnosis were experienced as it was necessary to access appropriate support and helpful to acknowledge (and potentially reframe) experiences, but could at times be experienced as a curse. ⁵³

Although many of these themes and negative impacts have been highlighted through different studies,^46–48 the positive impact of diagnosis on behavior and relationships is important.^53,61,62 The postdiagnosis strategies and small changes that can be made through understanding in terms of communication or decision-making, for instance, are very impactful. Whether it is communicating differently with peers or families or realizing that some relationships might not be healthy, these changes lead to better well-being, fewer mental health difficulties, and positive social impacts. A few studies have highlighted similar findings with diagnosis positively impacting quality of life, ⁶¹ allowing the creation of supportive environments ⁶² and fostering a sense of understanding and belonging. ⁵³ This has important implications in terms of support and how this could be used by therapists or peers in implementing change postdiagnosis.

In addition, the concept of timing and being ready for a diagnosis is also novel. This theme was primarily raised by the group of health care professionals who articulated the important notion of timing and preparing families/individuals for the diagnosis. They explained that this was essential in experiencing benefits from the process. Although only a minority of individuals experience receiving a diagnosis negatively, they explained that this was mainly due to not being ready, not being prepared for it. As one of the many benefits of a diagnosis is being able to implement change through understanding, this is not possible if the diagnosis is rejected. Only a couple of participants reported these negative impacts, and they were both close to retirement, with the negative impact mainly being the loss of time. They wondered what could have been and felt that it was too late to change, which created a lot of resentment. Participants also discussed timing in terms of how they felt that awareness of autism/ADHD had improved over time, with less stigma attached to these labels now than in previous decades. This meant that for some participants, they felt that their diagnosis had come at the best time for them and might have led to increased problems and loss of opportunities if they had perhaps been diagnosed earlier on in their life.

Strengths and limitations

This study has many strengths in its methodology and results. First, to our knowledge, it is the first study that looks at the experience of late diagnosis of autism/ADHD together. Most studies focus on one condition, but the commonalities between the experiences are so significant that it makes sense to not limit the sample to a specific diagnosis. This allows for the broader impact of neurodevelopmental conditions to be discussed. Second, by capturing both testimonies of service users and health care professionals, this study allows different viewpoints to be triangulated, reflecting a more comprehensive view of the diagnostic process and experiences compared with previous studies. The health care professionals’ accounts allowed us to capture a broader range of experiences through their years of supporting adults through an autism/ADHD diagnosis. Finally, this study reveals intricate difficulties with having undiagnosed autism/ADHD and the experience of a diagnosis that can be very useful for future research and also clinical care. For instance, the significant impact that living with undiagnosed autism/ADHD has on relationships and mental well-being is extremely important for supporting these groups in clinical settings. Every participant stated the significant impact of late diagnosis on their mental well-being, ranging from depression, lower self-esteem, or suicide attempts. In terms of research, future studies could further investigate the emerging concept of timing and being ready and its impact on the individuals’ reaction to diagnosis.

One of the limitations of this study is the lack of representation from other groups such as families or partners. While we would have liked to include another group reflecting the views of partners and/or family members, we were unable to recruit other groups within the scope of this study due to time and resource constraints. However, this would have allowed for a more external view of the experiences of the diagnosis that might reflect insight not noticed by service users or health care professionals.

Conclusion

This study highlights the many benefits and importance of receiving a diagnosis of autism/ADHD and the impact it has on multiple aspects of life such as mental well-being and relationships. The concept of being able to understand why you are different and why you might struggle at times was key in helping participants make positive changes in their lives. Although a few negative impacts were noted, the positive impact of diagnosis on healthier behavior and relationships is an important novel aspect that has many implications. Being ready and the timing of the diagnosis are also essential in experiencing any benefits postdiagnosis. We recommend that clinicians and service users familiarize themselves with the many impacts of receiving a diagnosis. Clinicians should consider the readiness of the adults seeking a diagnosis and prepare them for the potential negative reactions this might have. Service users can also often see a diagnosis as an end goal, an answer to years of struggle. However, the journey postdiagnosis is very tumultuous and can bring conflicting emotions and insight that are important to understand. This study is the first of its kind looking at autism/ADHD together and the similarity in experiences regardless of the label.

Authorship Confirmation Statement

B.F. wrote the article and S.C. revised it. B.F. and S.C. have developed the study together. B.F. conducted the analysis, which was reviewed, checked, and confirmed by S.C. The article has been submitted solely to Autism in Adulthood.