Autism spectrum disorders in the DSM-V: better or worse than the DSM-IV?

Autism in toddlers: can observation in preschool yield the same information as autism assessment in a specialised clinic?

We wanted to know whether preschool observation of children suspected of suffering from autism can provide the same information about core autism symptoms as the Autism Diagnostic Observation Schedule (ADOS) performed in a clinic. Forty 2–4-year-old children (9 girls, 31 boys), referred for assessment of suspected autism spectrum disorder participated in the study. The symptom areas covered by the ADOS algorithm were scored by an education specialist after free-field observation of each child in the preschool without using the prescribed ADOS materials. The ADOS was then completed in a clinic setting by examiners blind to the preschool results. Excellent agreement across results obtained at the two different types/settings of observations was found. The only significant difference found was with regard to spontaneous initiation of joint attention. The present study does not address the issue of whether or not one of the methods used is superior to the other when it comes to determining the “true” level of “autism problems” in these children. However, it is of interest that free-field preschool observation of children with suspected autism using a structured checklist yields very similar information as that obtained at ADOS assessment performed in a clinic setting.

How does relaxing the algorithm for autism affect DSM-V prevalence rates?

Although it is still unclear what causes autism spectrum disorders (ASDs), over time researchers and clinicians have become more precise with detecting and diagnosing ASD. Many diagnoses, however, are based on the criteria established within the Diagnostic and Statistical Manual of Mental Disorders (DSM); thus, any change in these diagnostic criteria can have a great effect upon children with ASD and their families. It is predicted that the prevalence of ASD diagnoses will dramatically decrease with the adoption of the proposed DSM-5 criteria in 2013. The aim of this current study was to inspect the changes in prevalence first using a diagnostic criteria set which was modified slightly from the DSM-5 criteria (Modified-1 criteria) and again using a set of criteria which was relaxed even a bit more (Modified-2 criteria). Modified-1 resulted in 33.77 % fewer toddlers being diagnosed with ASD compared to the DSM-IV, while Modified-2 resulted in only a 17.98 % decrease in ASD diagnoses. Children diagnosed with the DSM-5 criteria exhibited the greatest levels of autism symptomatology, but the Mod-1, Mod-2, and DSM-IV groups still demonstrated significant impairments. Implications of these findings are discussed.

The effectiveness of narrative therapy with young people with autism

PROBLEM

The aim of this pilot study was to be the first step toward empirically determining whether narrative therapy is effective in helping young people with autism who present with emotional and behavioral problems. Autism is increasingly being recognized in young people with average and above intelligence. Because of the nature of autism, these young people have difficulty navigating the challenges of school and adolescence. Narrative therapy can help them with their current difficulties and also help them develop skills to address future challenges. Narrative therapy involves working with a person to examine and edit the stories the person tells himself or herself about the world. It is designed to promote social adaptation while working on specific problems of living.

METHOD

This pilot intervention study used a convenience sample of 10 young people with autism (10-16 years) to evaluate the effectiveness of five 1 hr sessions of narrative therapy conducted over 10 weeks. The study used the parent-rated Strengths and Difficulties Questionnaire (SDQ) as the primary outcome measure. Secondary outcome measures were the Kessler-10 Scale of Psychological Distress (K-10), the Beck Hopelessness Scale, and a stress biomarker, the salivary cortisol to dehydroepiandrosterone (DHEA) ratio.

FINDINGS

Significant improvement in psychological distress identified through the K-10 was demonstrated. Significant improvement was identified on the Emotional Symptoms Scale of the SDQ. The cortisol:DHEA ratio was responsive and a power analysis indicated that further study is indicated with a larger sample.

CONCLUSION

Narrative therapy has merit as an intervention with young people with autism. Further research is indicated.

Discriminant analysis of the autism spectrum disorder observation for children

PURPOSE

To run a discriminant analysis on the individual items and the total scale of the ASD-OC to determine if they significantly discriminated between ASD and atypical groups.

METHOD

The measure was administered to 78 children as part of an outpatient evaluation.

RESULTS

The DA revealed that all of the items, excluding five, were significant predictors by themselves. Additionally, Wilks' lambda was significant, λ = 0.16, χ(2)= 115.91, p < 0.001 for the function, indicating that all of the items together significantly discriminated between groups. The DA was run again excluding those items mentioned above and the variability accounted for by all of the items and prediction of group membership decreased. Therefore, all 45 items were retained for inclusion in the final version of the ASD-OC.

CONCLUSION

The ASD-OC is able to discriminate between ASD and atypical groups.

What the DSM-5 portends for research, diagnosis, and treatment of autism spectrum disorders

In May 2013 the APA will release DSM-5, which will restructure the diagnostic classification for autism spectrum disorders (ASDs) into a single category. The proposed changes in DSM-5 aim to better reflect the current state of research by consistently identifying the core features in social/communication and restrictive and repetitive behaviors that are specific to ASDs. This review describes the empirical and theoretical bases of research in the nosology of ASDs, given the impending shift in DSM-5 diagnostic criteria. General issues in diagnosis and prevalence are described, with differences between DSM-IV and DSM-5 highlighted. To address concerns about the application of the proposed DSM-5 criteria, the current literature assessing the sensitivity and specificity of the proposed DSM-5 criteria is reviewed. Last, we discuss the implications of the changes in DSM-5 for the treatment of ASDs and recommend areas for future research.

Cognition in males and females with autism: similarities and differences

The male bias in autism spectrum conditions (ASC) has led to females with ASC being under-researched. This lack of attention to females could hide variability due to sex that may explain some of the heterogeneity within ASC. In this study we investigate four key cognitive domains (mentalizing and emotion perception, executive function, perceptual attention to detail, and motor function) in ASC, to test for similarities and differences between males and females with and without ASC (n = 128 adults; n = 32 per group). In the mentalizing and facial emotion perception domain, males and females with ASC showed similar deficits compared to neurotypical controls. However, in attention to detail and dexterity involving executive function, although males with ASC showed poorer performance relative to neurotypical males, females with ASC performed comparably to neurotypical females. We conclude that performance in the social-cognitive domain is equally impaired in male and female adults with ASC. However, in specific non-social cognitive domains, performance within ASC depends on sex. This suggests that in specific domains, cognitive profiles in ASC are modulated by sex.

Application of DSM-5 criteria for autism spectrum disorder to three samples of children with DSM-IV diagnoses of pervasive developmental disorders

OBJECTIVE

Substantial revisions to the DSM-IV criteria for autism spectrum disorders (ASDs) have been proposed in efforts to increase diagnostic sensitivity and specificity. This study evaluated the proposed DSM-5 criteria for the single diagnostic category of autism spectrum disorder in children with DSM-IV diagnoses of pervasive developmental disorders (PDDs) and non-PDD diagnoses.

METHOD

Three data sets included 4,453 children with DSM-IV clinical PDD diagnoses and 690 with non-PDD diagnoses (e.g., language disorder). Items from a parent report measure of ASD symptoms (Autism Diagnostic Interview-Revised) and clinical observation instrument (Autism Diagnostic Observation Schedule) were matched to DSM-5 criteria and used to evaluate the sensitivity and specificity of the proposed DSM-5 criteria and current DSM-IV criteria when compared with clinical diagnoses.

RESULTS

Based on just parent data, the proposed DSM-5 criteria identified 91% of children with clinical DSM-IV PDD diagnoses. Sensitivity remained high in specific subgroups, including girls and children under 4. The specificity of DSM-5 ASD was 0.53 overall, while the specificity of DSM-IV ranged from 0.24, for clinically diagnosed PDD not otherwise specified (PDD-NOS), to 0.53, for autistic disorder. When data were required from both parent and clinical observation, the specificity of the DSM-5 criteria increased to 0.63.

CONCLUSIONS

These results suggest that most children with DSM-IV PDD diagnoses would remain eligible for an ASD diagnosis under the proposed DSM-5 criteria. Compared with the DSM-IV criteria for Asperger's disorder and PDD-NOS, the DSM-5 ASD criteria have greater specificity, particularly when abnormalities are evident from both parents and clinical observation.

DSM-IV vs DSM-5 diagnostic criteria for toddlers with autism

PURPOSE

To evaluate prevalence rates of autism and autism symptomatology in toddlers using DSM-IV vs DSM-5 criteria.

METHOD

Two thousand seven hundred and twenty-one toddlers at risk for a developmental disability participated. DSM-IV and DSM-5 criteria were applied and overall prevalence using each set of criteria was established. Groups were also compared on BISCUIT-Part 1 scores to determine if groups differed on autism symptomatology.

RESULTS

DSM-5 resulted in 47.79% fewer toddlers being diagnosed with ASD compared to those on the DSM-IV. Toddlers diagnosed according to DSM-5 exhibited greater levels of autism symptomatology than those diagnosed with DSM-IV, but the latter group still exhibited significant levels of autism symptomatology.

CONCLUSION

The proposed DSM-5 will result in far fewer persons being diagnosed with ASD. These results replicate findings from two previous studies, with older children/adolescents and adults. As a result of these new criteria, far fewer people will qualify for needed autism services.

Computer-based interventions to improve social and emotional skills in individuals with autism spectrum disorders: a systematic review

OBJECTIVE

To review studies involving the use of computer-based interventions (CBI) to improve the social and emotional skills (e.g. emotional recognition) of individuals with autism spectrum disorders (ASD).

METHODS

The use of computer-based intervention (CBI) in the treatment of autism spectrum disorders (ASD) may offer some advantages to traditional one-to-one or group instruction including easier differentiation of instruction, decreased distractions and the incorporation of an individual's relative visual learning strengths. However, the results of past research suggest varying outcomes for CBI with individuals with ASD. This review provides a systematic analysis of studies investigating CBI to improve social and emotional skills (e.g. emotion recognition) of individuals with ASD. Electronic database searches and ancestral searches were used to identify studies that met pre-determined inclusion criteria. The included studies were then summarized in terms of: (a) participant characteristics, (b) social and emotional skills targeted, (c) details of the CBI, (d) results, and (e) certainty of evidence.

RESULTS

The results of these studies indicated that CBI's effect on social and emotional skills was mixed, with the majority of studies reporting unacceptable outcomes following intervention.

CONCLUSIONS

Overall, this review suggests that the use of CBI to improve the social and emotional skills of individuals with ASD is a promising practice. A comparison of CBI plus tutoring and face-to-face social skills training suggests that CBI can be as effective as face-to-face instruction. Practitioners should carefully consider the preferences and existing abilities of individuals with ASD and the customizability of the software when deciding to use CBI and selecting a software program.

Ultrasound and autism: association, link, or coincidence?

Autism spectrum disorders (ASDs) affect an estimated 1% of children in the United States. The etiology is probably multifactorial, including genetic components and exposure to infections, toxins, and other environmental factors, particularly unfavorable perinatal and neonatal conditions. There has been an increase in the frequency of diagnosis of ASDs over the last 20 years with a parallel increase in the use of obstetric diagnostic ultrasound, with prenatal ultrasound exposure mentioned as the possible main etiology for autism "epidemics." Central nervous system alterations have been described in ASDs, and certain similar changes have been described in animals after exposure to ultrasound. However, analysis of in utero exposure in humans has failed to show harmful effects in neonates or children, particularly in school performance, attention disorders, and behavioral changes. There is no independently confirmed peer-reviewed published evidence that a cause-effect relationship exists between in utero exposure to clinical ultrasound and development of ASDs in childhood. Ultrasound is a form of energy with effects in the tissues it traverses, and its use should be restricted to medical indications, by trained professionals, for as short a period and as low an intensity as compatible with accurate diagnosis.

Autism and the cognitive processing triad: a case for revising the criteria in the diagnostic and statistical manual

TOPIC

The next iteration of the Diagnostic and Statistical Manual of Mental Disorders is due for release in May 2013. The current diagnostic criteria for autism are based on a behavioral triad of impairment, which has been helpful for diagnosis and identifying the need for intervention, but is not useful with regard to developing interventions. Revised diagnostic criteria are needed to better inform research and therapeutic intervention.

PURPOSE

This article examines the research underpinning the behavioral triad of impairment to consider alternative explanations and a more useful framing for diagnosis and intervention.

SOURCES

Contemporary research and literature on autism were used in this study.

CONCLUSIONS

It is proposed that the cognitive processing triad of impaired abstraction, impaired theory of mind, and impaired linguistic processing become the triad of impairment for autism in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. These are investigable at the diagnostic level and can usefully inform intervention. Further, in addressing the debate on whether restrictive and repetitive behavior should remain central to diagnosis or be replaced by a deficit in imagination, the authors argue that both behavioral manifestations are underpinned by impaired abstraction.

A stable pattern of EEG spectral coherence distinguishes children with autism from neuro-typical controls - a large case control study

BACKGROUND

The autism rate has recently increased to 1 in 100 children. Genetic studies demonstrate poorly understood complexity. Environmental factors apparently also play a role. Magnetic resonance imaging (MRI) studies demonstrate increased brain sizes and altered connectivity. Electroencephalogram (EEG) coherence studies confirm connectivity changes. However, genetic-, MRI- and/or EEG-based diagnostic tests are not yet available. The varied study results likely reflect methodological and population differences, small samples and, for EEG, lack of attention to group-specific artifact.

METHODS

Of the 1,304 subjects who participated in this study, with ages ranging from 1 to 18 years old and assessed with comparable EEG studies, 463 children were diagnosed with autism spectrum disorder (ASD); 571 children were neuro-typical controls (C). After artifact management, principal components analysis (PCA) identified EEG spectral coherence factors with corresponding loading patterns. The 2- to 12-year-old subsample consisted of 430 ASD- and 554 C-group subjects (n = 984). Discriminant function analysis (DFA) determined the spectral coherence factors' discrimination success for the two groups. Loading patterns on the DFA-selected coherence factors described ASD-specific coherence differences when compared to controls.

RESULTS

Total sample PCA of coherence data identified 40 factors which explained 50.8% of the total population variance. For the 2- to 12-year-olds, the 40 factors showed highly significant group differences (P < 0.0001). Ten randomly generated split half replications demonstrated high-average classification success (C, 88.5%; ASD, 86.0%). Still higher success was obtained in the more restricted age sub-samples using the jackknifing technique: 2- to 4-year-olds (C, 90.6%; ASD, 98.1%); 4- to 6-year-olds (C, 90.9%; ASD 99.1%); and 6- to 12-year-olds (C, 98.7%; ASD, 93.9%). Coherence loadings demonstrated reduced short-distance and reduced, as well as increased, long-distance coherences for the ASD-groups, when compared to the controls. Average spectral loading per factor was wide (10.1 Hz).

CONCLUSIONS

Classification success suggests a stable coherence loading pattern that differentiates ASD- from C-group subjects. This might constitute an EEG coherence-based phenotype of childhood autism. The predominantly reduced short-distance coherences may indicate poor local network function. The increased long-distance coherences may represent compensatory processes or reduced neural pruning. The wide average spectral range of factor loadings may suggest over-damped neural networks.

Sex differences and autism: brain function during verbal fluency and mental rotation

Autism spectrum conditions (ASC) affect more males than females. This suggests that the neurobiology of autism: 1) may overlap with mechanisms underlying typical sex-differentiation or 2) alternately reflect sex-specificity in how autism is expressed in males and females. Here we used functional magnetic resonance imaging (fMRI) to test these alternate hypotheses. Fifteen men and fourteen women with Asperger syndrome (AS), and sixteen typically developing men and sixteen typically developing women underwent fMRI during performance of mental rotation and verbal fluency tasks. All groups performed the tasks equally well. On the verbal fluency task, despite equivalent task-performance, both males and females with AS showed enhanced activation of left occipitoparietal and inferior prefrontal activity compared to controls. During mental rotation, there was a significant diagnosis-by-sex interaction across occipital, temporal, parietal, middle frontal regions, with greater activation in AS males and typical females compared to AS females and typical males. These findings suggest a complex relationship between autism and sex that is differentially expressed in verbal and visuospatial domains.

Annual research review: re-thinking the classification of autism spectrum disorders

BACKGROUND

The nosology of autism spectrum disorders (ASD) is at a critical point in history as the field seeks to better define dimensions of social-communication deficits and restricted/repetitive behaviors on an individual level for both clinical and neurobiological purposes. These different dimensions also suggest an increasing need for quantitative measures that accurately map their differences, independent of developmental factors such as age, language level and IQ.

METHOD

Psychometric measures, clinical observation as well as genetic, neurobiological and physiological research from toddlers, children and adults with ASD are reviewed.

RESULTS

The question of how to conceptualize ASDs along dimensions versus categories is discussed within the nosology of autism and the proposed changes to the DSM-5 and ICD-11. Differences across development are incorporated into the new classification frameworks.

CONCLUSIONS

It is crucial to balance the needs of clinical practice in ASD diagnostic systems, with neurobiologically based theories that address the associations between social-communication and restricted/repetitive dimensions in individuals. Clarifying terminology, improving description of the core features of ASD and other dimensions that interact with them and providing more valid and reliable ways to quantify them, both for research and clinical purposes, will move forward both practice and science.

Intensive verhaltenstherapeutische Interventionsprogramme bei Autismus-Spektrum-Störungen

Autismus-Spektrum-Störungen (ASD) sind früh beginnende, persistierende Entwicklungsstörungen, die durch qualitative Beeinträchtigungen der sozialen Kommunikation und Sprache, der sozialen Interaktion sowie durch stereotypes Verhalten und Interessen charakterisiert sind. Für intensive verhaltenstherapeutische Interventionsprogramme, insbesondere nach Applied Behavior Analysis (ABA, „angewandte Verhaltensanalyse“), besteht bisher die beste Evidenz bei ASD-Behandlung. Sie zielen auf die Förderung eines breiten Spektrums an Fertigkeiten ab, wie die Verbesserung der kognitiven und Sprachentwicklung, des Anpassungsverhaltens und der motorischen Funktionen. Neuere Interventionsstudien zeigen einen Trend zur Fokussierung vor allem auf die Verbesserung der sozialen Kommunikation betroffener Kinder. Vorliegende Übersichtarbeit fasst eine Auswahl der bisher untersuchten, intensiven verhaltenstherapeutischen Interventionsprogramme und Elterntrainings für ASD zusammen, um in der klinischen Praxis die Entscheidung für eine evidenzbasierte Therapieempfehlung für betroffene Familien zu erleichtern.

Sensitivity and specificity of proposed DSM-5 diagnostic criteria for autism spectrum disorder

OBJECTIVE

This study evaluated the potential impact of proposed DSM-5 diagnostic criteria for autism spectrum disorder (ASD).

METHOD

The study focused on a sample of 933 participants evaluated during the DSM-IV field trial; 657 carried a clinical diagnosis of an ASD, and 276 were diagnosed with a non-autistic disorder. Sensitivity and specificity for proposed DSM-5 diagnostic criteria were evaluated using field trial symptom checklists as follows: individual field trial checklist items (e.g., nonverbal communication); checklist items grouped together as described by a single DSM-5 symptom (e.g., nonverbal and verbal communication); individual DSM-5 criterion (e.g., social-communicative impairment); and overall diagnostic criteria.

RESULTS

When applying proposed DSM-5 diagnostic criteria for ASD, 60.6% (95% confidence interval: 57%-64%) of cases with a clinical diagnosis of an ASD met revised DSM-5 diagnostic criteria for ASD. Overall specificity was high, with 94.9% (95% confidence interval: 92%-97%) of individuals accurately excluded from the spectrum. Sensitivity varied by diagnostic subgroup (autistic disorder = 0.76; Asperger's disorder = 0.25; pervasive developmental disorder-not otherwise specified = 0.28) and cognitive ability (IQ < 70 = 0.70; IQ ≥ 70 = 0.46).

CONCLUSIONS

Proposed DSM-5 criteria could substantially alter the composition of the autism spectrum. Revised criteria improve specificity but exclude a substantial portion of cognitively able individuals and those with ASDs other than autistic disorder. A more stringent diagnostic rubric holds significant public health ramifications regarding service eligibility and compatibility of historical and future research.

Testing the construct validity of proposed criteria for DSM-5 autism spectrum disorder

OBJECTIVE

To use confirmatory factor analysis to test the construct validity of the proposed DSM-5 symptom model of autism spectrum disorder (ASD), in comparison to alternative models, including that described in DSM-IV-TR.

METHOD

Participants were 708 verbal children and young persons (mean age, 9.5 years) with mild to severe autistic difficulties. Autistic symptoms were measured using the Developmental, Dimensional and Diagnostic interview (3Di). The fit of the two-factor DSM-5 model, which has a social communication and a restricted, repetitive behavior (RRB) factor, was compared with that of alternative models. In one half of the sample, properties of the DSM-5 model were examined to investigate the validity of specific diagnostic criteria, informing the development of a better fitting DSM-5 model. This was then cross-validated in the remaining "hold-out" half of the sample; and its stability was tested across groups defined by age, sex, and symptom severity.

RESULTS

The DSM-5 model was superior to the three-factor DSM-IV-TR model. It was improved by the removal of items measuring "play and imagination" and "stereotyped and repetitive use of language." A scale measuring sensory abnormalities was added to the model, and loaded onto its RRB factor. This DSM-5 model fit well in the hold-out sample; was stable across age and sex; and fit adequately in those with clinical and sub-threshold autistic presentations.

CONCLUSIONS

Among higher-functioning individuals, ASD is a dyad, not a triad, with distinct social communication and repetitive behavior dimensions. As suggested in the proposed DSM-5 criteria, sensory abnormalities are part of the RRB symptom cluster.

Language and communication skills in preschool children with autism spectrum disorders: contribution of cognition, severity of autism symptoms, and adaptive functioning to the variability

This study examined the contribution of cognitive function, severity of autism, and adaptive functioning to the variability in language and communication skills in 129 preschool children (aged 24-63 months) with autism spectrum disorder (ASD). Participants were selected from a representative research cohort of 208 preschool children on the basis of caregiver completion of the MacArthur-Bates Communicative Development Inventories (CDI). The children were classified into three cognitive groups: (a) Normal intelligence; (b) Developmental delay; and (c) Intellectual disability. Autism symptom severity was measured by the Autistic Behavior Checklist (ABC), and adaptive functioning by the Daily Living Skills (DLS) and Socialization (Soc) subscales from the Vineland Adaptive Behavior Scales. For each of five CDI variables (Phrases understood, Words understood, Words produced, Gestures and actions, and Language use), the contribution of cognition, severity of autism symptoms, and adaptive functioning to the variability was examined. Cognition and age explained about half or more of the variance in the four verbal language CDI variables, but only about one fourth of the variance in the non-verbal communication variable Gestures and actions. Severity of autism symptoms and the two adaptive measures (DLS and Soc) each only accounted for a few percent more of the variance in the four CDI language variables; however, for Gestures and actions, an additional 11-21% of the variance was accounted for. In conclusion, for children with ASD, receptive and expressive language is mainly related to cognitive level, whereas non-verbal communication skills seem to also be related to severity of autism symptoms and adaptive functioning.

Validation of proposed DSM-5 criteria for autism spectrum disorder

OBJECTIVE

The primary aim of the present study was to evaluate the validity of proposed DSM-5 criteria for autism spectrum disorder (ASD).

METHOD

We analyzed symptoms from 14,744 siblings (8,911 ASD and 5,863 non-ASD) included in a national registry, the Interactive Autism Network. Youth 2 through 18 years of age were included if at least one child in the family was diagnosed with ASD. Caregivers reported symptoms using the Social Responsiveness Scale and the Social Communication Questionnaire. The structure of autism symptoms was examined using latent variable models that included categories, dimensions, or hybrid models specifying categories and subdimensions. Diagnostic efficiency statistics evaluated the proposed DSM-5 algorithm in identifying ASD.

RESULTS

A hybrid model that included both a category (ASD versus non-ASD) and two symptom dimensions (social communication/interaction and restricted/repetitive behaviors) was more parsimonious than all other models and replicated across measures and subsamples. Empirical classifications from this hybrid model closely mirrored clinical ASD diagnoses (90% overlap), implying a broad ASD category distinct from non-ASD. DSM-5 criteria had superior specificity relative to DSM-IV-TR criteria (0.97 versus 0.86); however sensitivity was lower (0.81 versus 0.95). Relaxing DSM-5 criteria by requiring one less symptom criterion increased sensitivity (0.93 versus 0.81), with minimal reduction in specificity (0.95 versus 0.97).

CONCLUSIONS

Results supported the validity of proposed DSM-5 criteria for ASD as provided in Phase I Field Trials criteria. Increased specificity of DSM-5 relative to DSM-IV-TR may reduce false positive diagnoses, a particularly relevant consideration for low base rate clinical settings. Phase II testing of DSM-5 should consider a relaxed algorithm, without which as many as 12% of ASD-affected individuals, particularly females, will be missed. Relaxed DSM-5 criteria may improve identification of ASD, decreasing societal costs through appropriate early diagnosis and maximizing intervention resources.

A behavioral comparison of male and female adults with high functioning autism spectrum conditions

Autism spectrum conditions (ASC) affect more males than females in the general population. However, within ASC it is unclear if there are phenotypic sex differences. Testing for similarities and differences between the sexes is important not only for clinical assessment but also has implications for theories of typical sex differences and of autism. Using cognitive and behavioral measures, we investigated similarities and differences between the sexes in age- and IQ-matched adults with ASC (high-functioning autism or Asperger syndrome). Of the 83 (45 males and 38 females) participants, 62 (33 males and 29 females) met Autism Diagnostic Interview-Revised (ADI-R) cut-off criteria for autism in childhood and were included in all subsequent analyses. The severity of childhood core autism symptoms did not differ between the sexes. Males and females also did not differ in self-reported empathy, systemizing, anxiety, depression, and obsessive-compulsive traits/symptoms or mentalizing performance. However, adult females with ASC showed more lifetime sensory symptoms (p = 0.036), fewer current socio-communication difficulties (p = 0.001), and more self-reported autistic traits (p = 0.012) than males. In addition, females with ASC who also had developmental language delay had lower current performance IQ than those without developmental language delay (p<0.001), a pattern not seen in males. The absence of typical sex differences in empathizing-systemizing profiles within the autism spectrum confirms a prediction from the extreme male brain theory. Behavioral sex differences within ASC may also reflect different developmental mechanisms between males and females with ASC. We discuss the importance of the superficially better socio-communication ability in adult females with ASC in terms of why females with ASC may more often go under-recognized, and receive their diagnosis later, than males.