Autism spectrum conditions (ASC) develop early in life and are thought to last a lifetime. However, ASC research has two major knowledge gaps that hinder progression in understanding the concept of ASC and in providing proper support for autistic adults: (1) the majority of knowledge about ASC mainly stems from childhood studies so little is known about older autistic adults and (2) while it is broadly recognised that ASC is a heterogeneous condition, we do not yet understand the differences in trajectories leading to their future outcome. We aim to fill both knowledge gaps.

A multistage overlapping cohort design assessing (cognitive) ageing in ASC is designed to obtain an accelerated longitudinal data set. Data, including a multitude of questionnaires, diagnostics and cognitive tests, are collected over four waves within a 10-year time frame. This will provide information regarding actual changes in quality of life, co-occurring health conditions and cognition as well as the possibility to test external validity and temporal stability in newly formed behavioural subtypes. Participants consist of three groups of adults aged 20–90 years: (1) with a clinical diagnosis of ASC, (2) with a clinical diagnosis of attention deficit hyperactivity disorder (ADHD) but no ASC, (3) no ASC/ADHD (ie, comparison group). The sample size differs between waves and instruments. Detailed analysis plans will be preregistered in AsPredicted or at the Open Science Framework.

Substantial increases in the relative and absolute number of older persons in our society pose a challenge for biology, social and behavioral science, and medicine. Successful aging is multidimensional, encompassing the avoidance of disease and disability, the maintenance of high physical and cognitive function, and sustained engagement in social and productive activities. Research has identified factors predictive of success in these critical domains. The stage is set for intervention studies to enhance the proportion of our population aging successfully.

Children and adolescents with autism spectrum disorder (ASD) have many well-known health concerns, yet health conditions in adults with ASD remain poorly defined. To examine health conditions and functional status in adults with ASD and identify factors associated with health and functional status across age cohorts.We collected cross-sectional data from 255 adult subjects aged 18 to 71 years with ASD using the Rochester Health Status Survey IV (RHSS-IV), a 58-item validated survey instrument. We used the National Health and Nutritional Examination Survey and National Health Interview Survey to provide comparative prevalence rates in the general population.

General health status in adult populations with autism spectrum disorders has been little studied. We aimed to investigate general health status and predictors of poor health in adults with autism spectrum disorders compared with other adults. Whole country data were drawn from Scotland’s Census, 2011. We calculated and compared the frequencies of health status in adults with and without autism spectrum disorders. We then used logistic regressions to calculate odds ratios (OR) with 95% confidence intervals (95% CI) of autism predicting poor general health in the whole population, adjusted for age and gender, and OR (95% CI) of age and gender predicting poor general health within the autism spectrum disorders population.

Previous research has shown that relatively few adults with autism have a paid job or live on their own. However, outcomes also vary a lot and may depend on many different factors. In this study, we examined the level of functioning and happiness of 917 adults with autism (425 men and 492 women) aged 18–65 years. Most of them were of average to high intellectual ability. Over 6 years, we measured whether they had a paid job, close friendships and lived on their own (i.e. their objective functioning). We also measured how happy they felt. Objectively, most autistic adults did fairly to very well. Those with better objective outcomes (e.g. those with paid work) also tended to be happier. Most adults improved in objective functioning and happiness over 6 years. Participants with a lower intellectual ability, more autism traits, mental health problems and younger age had poorer objective outcomes. Participants with more autism traits and mental health problems were less happy. Autistic men and women functioned at similar levels and were equally happy. We found important factors that predict a better (or worse) outcome for autistic adults. Overall, compared with some previous research, our findings give a more positive picture of the outcomes for autistic adults with average to high intellectual abilities.

Adult autism studies are increasingly comprised of later-diagnosed adults, yet little is known about how these adults compare to those diagnosed earlier in life. The present study examines medical and psychiatric conditions endorsed by autistic adults and documents differences between those diagnosed with ASD in childhood versus adulthood, as well as across age groups and sex at birth. 4657 legally independent adults (ages 18–85, M = 33.4 years) with professional ASD diagnoses who completed a medical questionnaire were drawn from the Simons Powering Autism Research Knowledge (SPARK) study. Chi square analyses, t-tests, and logistic regressions were used to compare medical and psychiatric conditions between age groups, sex at birth and adults diagnosed in childhood (before age 21) versus adulthood (at or after 21 years). Overall number of conditions endorsed as being diagnosed by a professional was high, with an average of 1.69 (SD = 2.01) medical or developmental and 2.98 (SD = 2.29) psychiatric conditions reported across the sample. Females were more likely to endorse psychiatric conditions (OR = 1.68). Adult-diagnosed adults were more likely to endorse psychiatric conditions (OR = 2.71) and reported more lifetime psychiatric diagnoses (M = 3.15, SD = 2.23) than their childhood-diagnosed counterparts (M = 2.81, SD = 2.33). These findings underscore the need for research to better understand and treat co-occurring psychiatric conditions in autistic adults and report and consider the age of diagnosis in adult autism samples. Moreover, results suggest it is imperative that mental health professionals receive autism training to promote accurate differential diagnosis and equitable access to mental health care for autistic adults with co-occurring psychiatric conditions.

Although psychiatric problems are less prevalent in old age within the general population, it is largely unknown whether this extends to individuals with autism spectrum disorders (ASD). We examined psychiatric symptoms and disorders in young, middle-aged, and older adults with and without ASD (Nmax = 344, age 19–79 years, IQ > 80). Albeit comparable to other psychiatric patients, levels of symptoms and psychological distress were high over the adult lifespan; 79 % met criteria for a psychiatric disorder at least once in their lives. Depression and anxiety were most common. However, older adults less often met criteria for any psychiatric diagnosis and, specifically, social phobia than younger adults. Hence, despite marked psychological distress, psychiatric problems are also less prevalent in older aged individuals with ASD.

Autism spectrum conditions were once seen as a predominantly male condition, but this has caused research to have little focus on women. Therefore, little is known about menstruation and menopause in autism spectrum conditions. Some smaller studies indicate that autistic individuals might suffer from increased difficulties surrounding these events. This study aimed to investigate whether autistic women experience more frequent premenstrual dysphoric disorder, causing extreme physical, emotional, and functional impairment. In a partly overlapping sample, we also examined whether women with autism spectrum condition experience increased complaints surrounding menopause. We did not find an increased prevalence of premenstrual dysphoric disorder in autism spectrum conditions (14.3%) compared with non-autistic women (9.5%). Those with autism spectrum conditions did experience increased menopausal complaints. These menopausal complaints were associated with higher levels of depression and autistic traits. In non-autistic women, menopausal complaints were associated with increased inattention, hyperactivity/impulsivity (i.e. attention deficit hyperactivity disorder traits), and depression. With this work, we show the important role that major reproductive milestones can have in an autistic woman’s life.

Camouflaging behavior is often defined as using strategies to hide autistic characteristics. In this study, we investigated how to measure camouflaging behavior by performing a conceptual replication of the original study of the Camouflaging Autistic Traits Questionnaire (CAT-Q) and testing whether the self-reported camouflaging behavior is measuring the same construct as the second most used manner to measure camouflaging behavior, the discrepancy method.In total, 674 individuals (356 autistic) aged 30–92 years, filled out the Dutch translation of the CAT-Q (CAT-Q-NL) and the Autism Spectrum Quotient (AQ). In 90 autistic adults the Autism Diagnostic Observation Schedule (ADOS-2) was administered. We executed preregistered analyses (AsPredicted #37800) to investigate the factor structure, measurement invariance, internal consistency, convergent validity and group differences.

Autism is heterogeneous, which complicates providing tailored support and future prospects. We aim to identify subgroups in autistic adults with average to high intelligence, to clarify if certain subgroups might need support. We included 14 questionnaire variables related to aging and/or autism (e.g., demographic, psychological, and lifestyle). Community detection analysis was used for subgroup identification in an original sample of 114 autistic adults with an adulthood diagnosis (autism) and 58 non-autistic adults as comparison group (COMP), and a replication sample (NAutism = 261; NCOMP = 287), both aged 30–89 years. Next, we identified subgroups and assessed external validity (for cognitive and psychological difficulties, and quality of life [QoL]) in the autism samples. To test specificity, we repeated the analysis after adding 123 adults with ADHD, aged 30–80 years. As expected, the autism and COMP groups formed distinct subgroups. Among autistic adults, we identified three subgroups of which two were replicated. One of these subgroups seemed most vulnerable on the cluster variables; this subgroup also reported the most cognitive and psychological difficulties, and lowest QoL. Adding the ADHD group did not alter results. Within autistic adults, one subgroup could especially benefit from support and specialized care, although this must be tested in future studies.

While there is emerging evidence on the prevalence of physical and mental health conditions among autistic adults, less is known about this population’s needs during older adulthood (aged 65+). We conducted a cross-sectional retrospective cohort study of 2016–2017 Medicare data to compare the prevalence of physical and mental health conditions in a national sample of autistic older adults (N = 4685) to a matched population comparison (N = 46,850) cohort. Autistic older adults had significantly greater odds of nearly all physical health conditions including epilepsy (odds ratio = 18.9; 95% confidence interval = 17.2–20.7), Parkinson’s disease (odds ratio = 6.1; 95% confidence interval = 5.3–7.0), and gastrointestinal conditions (odds ratio = 5.2; 95% confidence interval = 4.9–5.5). Most mental health conditions were more common among autistic older adults, including schizophrenia and psychotic disorders (odds ratio = 25.3; 95% confidence interval = 22.4–28.7), attention deficit disorders (odds ratio = 24.4; 95% confidence interval = 16.2–31.0), personality disorders (odds ratio = 24.1; 95% confidence interval = 17.8–32.5), and suicidality or self-inflicted injury (odds ratio = 11.1; 95% confidence interval = 8.9–13.8). Health conditions commonly associated with advanced age in the general population (e.g. osteoporosis, cognitive disorders, heart disease, cancer, cerebrovascular disease, osteoarthritis) were also significantly more common among autistic older adults. By highlighting the significant physical and mental health needs for which autistic older adults require care, our findings can inform healthcare systems, healthcare providers, and public health initiatives seeking to promote well-being in this growing population.

Longitudinal studies on cognitive aging in autism are scarce, and largely underpowered, yet essential to obtain more conclusive results on cognitive changes in autism during adulthood. In the largest longitudinal study on cognition thus far, we aimed to get more insight into cognitive aging in autism. As pre-registered, we computed reliable change indices (RCIs) and multilevel models to estimate cognitive changes in 128 autistic, and 112 non-autistic adults (range: 24–85 yrs.) over two to three timepoints (average interval: 3.5 yrs.). Participants were tested on 15 outcome measures, covering verbal memory, visual (working) memory, prospective memory, theory of mind, fluency, response speed, inhibition, planning, and switching. RCIs showed no significant differences between groups (autism/no-autism) in changes over time. Using multilevel models, most tasks showed sensitivity to cross-sectional age-related effects, and/or longitudinal changes, with worse performance at older age, and later timepoints. However, effects were not significantly different between the autism and no-autism group. This lack of group differences was substantiated by additional Bayesian analyses. In sum, the current study provides evidence for parallel (similar) cognitive aging in autism. Specifically, autistic individuals diagnosed in adulthood, without intellectual disability, do not seem at risk for accelerated cognitive decline.

It is largely unknown how age impacts cognition in autism spectrum disorder (ASD). We investigated whether age-related cognitive differences are similar, reduced or increased across the adult lifespan, examined cognitive strengths and weaknesses, and explored whether objective test performance is related to subjective cognitive challenges. Neuropsychological tests assessing visual and verbal memory, generativity, and theory of mind (ToM), and a self-report measure assessing cognitive failures were administered to 236 matched participants with and without ASD, aged 20–79 years (IQ > 80). Group comparisons revealed that individuals with ASD had higher scores on visual memory, lower scores on generativity and ToM, and similar performance on verbal memory. However, ToM impairments were no longer present in older (50+ years) adults with ASD. Across adulthood, individuals with ASD demonstrated similar age-related effects on verbal memory, generativity, and ToM, while age-related differences were reduced on visual memory. Although adults with ASD reported many cognitive failures, those were not associated with neuropsychological test performance. Hence, while some cognitive abilities (visual and verbal memory) and difficulties (generativity and semantic memory) persist across adulthood in ASD, others become less apparent in old age (ToM). Age-related differences characteristic of typical aging are reduced or parallel, but not increased in individuals with ASD, suggesting that ASD may partially protect against an age-related decrease in cognitive functioning. Despite these findings, adults with ASD experience many cognitive daily challenges, which highlights the need for adequate social support and the importance of further research into this topic, including longitudinal studies.

We investigated whether our previous findings on cognitive aging in autism could be confirmed in a new study measuring the cognitive effects of age in autistic and non-autistic adults. As expected, tasks that younger autistic adults had difficulties with (theory of mind, fluency) were also difficult for older autistic adults, and the effect of age itself was similar in autistic and non-autistic adults. Unexpectedly, we observed no protective effects (less cognitive aging) in autism.

This study used a self-report dementia screener to look at increasing problems in thinking and memory in middle and older age autistic adults. Rates of thinking and memory problems were high, with 30% of the autistic adults reporting experiences of cognitive decline. Autistic individuals designated female at birth and adults with greater autistic traits were more likely to screen positive for likely cognitive decline.

While the increased incidence of dementia and subjective cognitive complaints (SCCs) suggests that autistic adults may face cognitive challenges at older age, the extent to which SCCs predict (future) cognitive functioning remains uncertain. This uncertainty is complicated by associations with variables like depression. The current study aims to unravel the interplay of age, depression, cognitive performance, and SCCs in autism. Using a large cross-sectional cohort of autistic (n=202) and non-autistic adults (n=247), we analyzed associations of SCCs with age, depression, and cognitive performance across three domains (visual memory, verbal memory, and fluency). Results showed a strong significant association between depression and SCCs in both autistic and non-autistic adults. Cognitive performance was not significantly associated with SCCs, except for a (modest) association between visual memory performance and SCCs in autistic adults only. Follow-up regression tree analysis indicated that depression and being autistic were considerably more predictive of SCCs than objective cognitive performance. Age nor sex was significantly associated with SCCs. These findings indicate that self-reported cognitive functioning does not equal cognitive performance, and should be interpreted with care, especially in individuals with high rates of depression. Longitudinal investigations are needed to understand SCCs’ role in dementia and cognitive health in autism.

Little is known about the cognitive profile of middle-aged and older autistic or high autistic trait adults. Using data from the PROTECT cohort and a well-validated online cognitive assessment platform, the findings from the current study suggest that higher autistic traits are associated with worse cognitive functioning throughout later adulthood. This suggests that older adults with high autistic traits may require additional support as they age.

Longitudinal studies on cognitive aging in autism are scarce, and largely underpowered, yet essential to obtain more conclusive results on cognitive changes in autism during adulthood. In the largest longitudinal study on cognition thus far, we aimed to get more insight into cognitive aging in autism. As pre-registered, we computed reliable change indices (RCIs) and multilevel models to estimate cognitive changes in 128 autistic, and 112 non-autistic adults (range: 24–85 yrs.) over two to three timepoints (average interval: 3.5 yrs.). Participants were tested on 15 outcome measures, covering verbal memory, visual (working) memory, prospective memory, theory of mind, fluency, response speed, inhibition, planning, and switching. RCIs showed no significant differences between groups (autism/no-autism) in changes over time. Using multilevel models, most tasks showed sensitivity to cross-sectional age-related effects, and/or longitudinal changes, with worse performance at older age, and later timepoints. However, effects were not significantly different between the autism and no-autism group. This lack of group differences was substantiated by additional Bayesian analyses. In sum, the current study provides evidence for parallel (similar) cognitive aging in autism. Specifically, autistic individuals diagnosed in adulthood, without intellectual disability, do not seem at risk for accelerated cognitive decline.

Aiming to understand cognitive differences between autistic adults, we applied a new statistical method that assesses cognition in a sensitive, and individual manner. Cognitive profiles of autistic adults, and non-autistic adults were, therefore, investigated statistically. About twice as many autistic individuals showed a different cognitive profile (20%) as compared to non-autistic individuals, yet most autistic individuals (80%) did not. Differences were, in part, explained by differences in psychological distress.

A significant proportion of autistic adults today were not diagnosed until later in life, a group referred to as the ‘lost generation,’ which may affect mental health. In Study 1 we explored quality of life and autistic trait levels in 420 autistic and TD adults, and in Study 2 we explored the experiences of 8 autistic adults diagnosed as adults. We found that autistic adults had lower quality of life outcomes and higher autistic trait levels which related to age of diagnosis, and qualitative findings indicated that while adults were empowered by their new diagnosis, they still require specialized supports. Our findings are discussed, emphasizing future directions and implications for the current care system in place for autistic adults.

In a large sample of independent autistic adults, those diagnosed with ASD after 21 years of age indicated having more psychiatric diagnoses than those diagnosed before 21 years of age. This highlights the importance of considering age of ASD diagnosis in research and underscores a need for autism training in the broader mental health field.

Previous research has shown that relatively few adults with autism have a paid job or live on their own. However, outcomes also vary a lot and may depend on many different factors. In this study, we examined the level of functioning and happiness of 917 adults with autism (425 men and 492 women) aged 18–65 years. Most of them were of average to high intellectual ability. Over 6 years, we measured whether they had a paid job, close friendships and lived on their own (i.e. their objective functioning). We also measured how happy they felt. Objectively, most autistic adults did fairly to very well. Those with better objective outcomes (e.g. those with paid work) also tended to be happier. Most adults improved in objective functioning and happiness over 6 years. Participants with a lower intellectual ability, more autism traits, mental health problems and younger age had poorer objective outcomes. Participants with more autism traits and mental health problems were less happy. Autistic men and women functioned at similar levels and were equally happy. We found important factors that predict a better (or worse) outcome for autistic adults. Overall, compared with some previous research, our findings give a more positive picture of the outcomes for autistic adults with average to high intellectual abilities.

It is well established that very few individuals with autism spectrum disorders (ASD) and an IQ below 70 are able to live independently as adults. However, even amongst children with an IQ in the normal range, outcome is very variable. Childhood factors that predict later stability, improvement or decline in cognitive functioning remain uncertain and, in particular, very little is known about trajectories in later adulthood. Changes in cognitive and language ability from childhood to adulthood were assessed in 60 individuals with autism, all of whom had an IQ in the average range as children. Mean age in childhood = 6 years (range 2–13 years); mean age in adulthood = 44 years (range 29–64 years). Trajectories of change and factors related to current cognitive abilities were explored.

It is unclear whether adults diagnosed with autism spectrum disorder (ASD) are at higher risk of being diagnosed with early-onset dementia compared to those who are not on the autism spectrum. In this study we examined for the first time the nationwide prevalence and incidence of Alzheimer’s Disease and other types of dementia in ASD in a sample of adults with ASD aged 30–64 years who were enrolled in Medicaid, the largest insurer of behavioral health services in the US. Medicaid claims data, which include information on the diagnoses that beneficiaries receive, suggested that the adults with ASD were approximately 2.6 times more likely to be diagnosed with early-onset Alzheimer’s disease and related dementias compared to the general population.

The integrity and connectivity of the frontal lobe, which subserves fluency, may be compromised by both ASD and aging. Alternate networks often integrate to help compensate for compromised functions during aging. We used network analyses to study how compensation may overcome age-related compromised in individuals with ASD. Participants consisted of middle-aged (40–60; n = 24) or young (18–25; n = 18) right-handed males who have a diagnosis of ASD, and age- and IQ-matched control participants (n = 20, 14, respectively). All performed tests of language and executive functioning and a fluency functional MRI task. We first used group individual component analysis (ICA) for each of the 4 groups to determine whether different networks were engaged. An SPM analysis was used to compare activity detected in the network nodes from the ICA analyses.