Diagnosis Of Autistic Disorder Research Articles

High-Functioning Autism and Asperger’s Disorder: Utility and Meaning for Families

We used framework analysis to investigate the utility of pervasive developmental disorder diagnoses, interviewing young people (aged 9-16 years) with high-functioning autistic disorder (AD) and Asperger's disorder (AsD), and their parents. Twenty two participants from ten families described both gains and costs resulting from diagnosis. Perceived advantages of AD and AsD diagnosis were increased understanding and practical support, and parental empowerment. Disadvantages included the effects of stigma and concerns about validity. Participants tended to consider AsD and AD as interchangeable terms. Findings suggest that the utility of AD and AsD depends upon both their validity and how these diagnoses are received in their cultural, economic and legislative context. Improvement of post-diagnostic services will improve the utility of AD and AsD.

Follow up of Children with Autism Spectrum Disorders: Stability and Change in Diagnosis

To assess diagnostic stability of initial autism spectrum disorder (ASD) diagnosed in children three years or less. Participants in the study included 77 (64 boys,13 girls) children in whom a diagnosis of Autistic Disorder (AD) and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) was made at age 3 years or less as per the DSM IV criteria. Children were recruited from the Outpatient services of the department of Pediatrics, Post Graduate Institute of Medical Education and Research, Chandigarh. Multi-disciplinary evaluations including neurological, diagnostic, cognitive, and behavioral assessments were made. In addition, the Childhood Autism Rating Scale (CARS) was administered to assess symptom severity. Follow up was done around 4 years of age. At Time 1, 64 (83.11%) children were diagnosed as AD and 13 (16.88%) children with PDD-NOS. Follow up was possible in only 43 children (55.8%) at the mean age of 4 years 1 month (SD = 0.99) after a mean age interval of 1.65 years (SD = 0.95). At Time 2, 37 (86%) children were diagnosed as AD and 4 (9.3%) children were diagnosed with PDD-NOS, and 2 (4.65%) children were found to be off the ASD spectrum. The diagnosis of ASD (AD and PDD-NOS) was stable over time and 41 (95.3%) out of 43 children retained an ASD diagnosis. Looking at specific ASD diagnosis, AD diagnosis was stable for 33 out of 37 (89.18%) children and the PDD-NOS was stable for only 1 out of 6 (16.67%) children. An early and a stable diagnosis of ASD is possible provided there are expert clinicians available. Early detection and diagnosis of ASDs allows opportunities for children to profit more from early supports and interventions.

A pilot study on the diagnostic performance of DMS-IV and DMS-V for autism spectrum disorder

The new diagnostic criteria for autism spectrum disorders (ASD) are due to be released in May 2013. The impact of changes made in the new criteria is yet to be evaluated. Here we performed a retrospective study on a cohort of ASD patients diagnosed by DSM-IV criteria, aimed to compare the diagnostic performances between DSM-IV and DSM-V. We reviewed the medical records of 163 patients with possible clinical diagnosis of ASD. Ninty-three (57%) of them met the DSM-IV criteria for Autistic disorder, the rest 70 cases were either PDD-NOS (n=39) or Asperger’s disorder (n=3) or without sufficient information in medical record to perform a clinical diagnosis (n=28). Upon re-evaluation using the new diagnostic criteria in DSM-V, only 60% of patients with previous diagnosis of autistic disorder met the new criteria. One individual who was previous diagnosed as PDD-NOS met the new diagnostic criteria for autistic disorder. The present study revealed a significant difference in diagnostic yield by new and old criteria. This pilot comparative study reveals that the ASD diagnostic criteria in DSM-V are stricter than that in DSM-IV and autism patients diagnosed using DMS-V criteria tend to be more severely affected. The new criteria will have immediate impact on the clinical diagnosis and management of individuals with neuodevelopmental disorders and it will affect the prevalence estimate of ASD in population as well.

Information et vécu parental du diagnostic de l’autisme. I. Premières identifications et nature des premières inquiétudes

The purpose of the present study is to provide the current state of knowledge concerning the contribution of parental experiences in early identification and diagnostic patterns of children with autism spectrum disorder. As developmental disorder, professionals’ diagnosis is necessarily informed by parental recognition of symptoms and their nature. Timing of initial symptom recognition and parents’ initial concerns differ from timing of diagnosis. In addition, parental concerns are not confined to the specific symptoms of autism that professionals differ. We try to examine factors which determines whether early recognition and diagnosis of autistic disorder in children.

Age of diagnosis for autism: individual and community factors across 10 birth cohorts

BackgroundThe incidence of autism rose dramatically between 1992 and 2001, while the age at which children were first diagnosed declined. During this period the size and composition of the autism...

Using IPTW Marginal Structural Modeling to Balance Confounding by Indication

S (ACE) AEP Vol. 20, No. 9 September 2010: 691–724 718 categories ranging from documented clinical diagnosis of Autism to suspicionofASDwithnodiagnostic or educational documentation. Changes in the distribution of cases across categories both by time and presence of IntellectualDisability were modeled using Bayesian multinomial regression. RESULTS: We observed an increase in the proportion of children with a clinical diagnosis of Autistic Disorder from 2002 onwards and a decrease in the proportion suspected of ASD with no clinical or school documentation. Among children without an ID, there was a similarly timed increase in the proportion receiving school services for ASD without a clinical diagnosis. CONCLUSION: Using a Bayesian approach provided a number of analytic and interpretive advantages including direct estimation of uncertainty concerning the true classification probabilities through the posterior distributions and the ability to evaluate changes in the the classification probabilities without the interpretive difficulty associated with sampling-based inference in the more common frequentist approach. P76 A DEMONSTRATION OF MULTILEVEL, SMALL AREA MODELING: ESTIMATING HPV VACCINE COVERAGE IN TEXAS COUNTIES JM Eberth, MDM Hossain, SW Vernon, JA Tiro, University of Texas School of Public Health, Houston TX PURPOSE: Local health data can be used in policy development, resource allocation, program planning, hypothesis generation, and health disparities research. Methods to produce local estimates using data collected for larger regions are known as small area estimation (SAE). Here, we demonstrate the use of model-based SAE to estimate HPV vaccine coverage. METHODS: Graphically and quantitatively, we show the steps involved in the development and evaluation of amultilevel, small area (SA) model for estimating HPV vaccine coverage among girls aged 11–17. The outcome ( 1 dose Gardasil or HPV4) and level 1 predictors were obtained from the 2008 Texas Behavioral Risk Factor Surveillance System. Level 2 predictors and county population counts were obtained from auxiliary datasets. RESULTS: The predicted probabilities from our SAmodel were linked with demographic-specific population counts from the U.S. Census to derive county level estimates of HPV vaccine coverage. Preliminary analyses show geographic variability in HPV vaccine coverage at the county level, with estimates ranging from w10–40%. Only 1 county (i.e. Loving County) had too few residents to estimate HPV vaccine coverage among girls aged 11–17. The 2008 National Immunization Survey estimates 32% of girls aged 13-17 in TX have obtained at least 1 dose of HPV4. CONCLUSION: Although geographic variability in HPV vaccination has been previously reported, our study is the first to predict coverage rates at the county level using model-based SAE.

Longitudinal Magnetic Resonance Imaging Study of Cortical Development through Early Childhood in Autism

Cross-sectional magnetic resonance imaging (MRI) studies have long hypothesized that the brain in children with autism undergoes an abnormal growth trajectory that includes a period of early overgrowth; however, this has never been confirmed by a longitudinal study. We performed the first longitudinal study of brain growth in toddlers at the time symptoms of autism are becoming clinically apparent using structural MRI scans at multiple time points beginning at 1.5 years up to 5 years of age. We collected 193 scans on 41 toddlers who received a confirmed diagnosis of autistic disorder at approximately 48 months of age and 44 typically developing controls. By 2.5 years of age, both cerebral gray and white matter were significantly enlarged in toddlers with autistic disorder, with the most severe enlargement occurring in frontal, temporal, and cingulate cortices. In the longitudinal analyses, which we accounted for age and gender effect, we found that all regions (cerebral gray, cerebral white, frontal gray, temporal gray, cingulate gray, and parietal gray) except occipital gray developed at an abnormal growth rate in toddlers with autistic disorder that was mainly characterized by a quadratic age effect. Females with autistic disorder displayed a more pronounced abnormal growth profile in more brain regions than males with the disorder. Given that overgrowth clearly begins before 2 years of age, future longitudinal studies would benefit from inclusion of even younger populations as well as further characterization of genetic and other biomarkers to determine the underlying neuropathological processes causing the onset of autistic symptoms.

Signes neurologiques mineurs et troubles envahissants du développement

Many studies have focused on specific motor signs in autism and Asperger's syndrome, but few has been published on the complete range of neurological soft signs (NSS) in children with pervasive developmental disorder (PDD). Scarce are the studies evaluating NSS in children suffering from PDD not otherwise specified (PDDNOS). This study compared performance of 11 autistic children (AD) and 10 children with PDDNOS, with controls matched on age, sex and cognitive performance on Krebs et al.'s NSS scale. Because of the duration of the assessments and specific difficulties encountered in managing some items, an adaptation of the scale had to be made during a pilot study with the agreement of the author. To be eligible, patients had to meet the following inclusion criteria: an age range of 6-16 years, a diagnosis of autistic disorder or PDDNOS based on the DSMIV criteria (American Psychiatric Association 1994). The autism diagnostic interview-revised (ADI-R) was used in order to confirm the diagnosis and to evaluate the association of the symptoms to the severity of the NSS. The childhood autism rating scale (CARS) was completed for the patients in order to evaluate symptoms at the time of the NSS examination. Cognitive ability was assessed with Raven's progressive matrices. Were excluded patients with: history of cerebral palsy, congenital anomaly of the central nervous system, epilepsy, known genetic syndrome, tuberous sclerosis, neurofibromatosis, antecedent of severe head trauma, Asperger's syndrome, obvious physical deformities or sensory deficits that would interfere with neurological assessment, deep mental retardation and recent or chronic substance use or abuse. Healthy controls shared the same exclusion criteria, with no personal history of neurological, psychiatric disorder or substance abuse, no family history of psychiatric disorder and normal or retardation in schooling. All study procedures were approved by the local Ethics Committee (Comité d'éthique, Razi Hospital), according to the declaration of Helsinki. There was no difference between patients and controls with respect to sex, age and cognitive function. All children had an IQ higher than 81. Significant differences were found between AD children and control group in the motor integration function and sensory integration function. Different NSS scores were significantly higher in the PDDNOS group than in controls: the total scores, motor coordination, motor integration function, sensory integration and abnormal movements. Lower performance in motor coordination skills was associated with higher ADI-R communication score in the AD group. No relationship was found between NSS and CARS' total sore. This study confirms the impaired neurological functioning in autistic as well as PDDNOS children. The association of motor impairment with autistic symptoms highlights the argument that motor control problems can be part of the autism spectrum disorders. The lack of relationship between NSS and intellectual aptitude in the clinical sample provides new elements for the neurodevelopment model of the autism spectrum.

Brief Report: Acamprosate in Fragile X Syndrome

Glutamatergic dysfunction is implicated in the pathophysiology of fragile X syndrome (FXS). We report on the first trial of acamprosate, a drug with putative mGluR5 antagonism, in three adults with FXS and autism. Medical records describing open-label treatment with acamprosate in 3 patients with FXS and a comorbid diagnosis of autistic disorder were reviewed. In all three patients, acamprosate was associated with improved linguistic communication. Three patients received acamprosate over a mean 21.3 weeks of treatment. All patients showed global clinical benefit as rated with the Clinical Global Impressions-Improvement scale. Marked communication improvement was unexpected and has potential implications for the treatment of FXS, as well as idiopathic autism.

APA Makes DSM-5 Proposals Available for Comment

APA Makes <i>DSM-5</i> Proposals Available for Comment

Sensitivity of the Autism Behavior Checklist in Indian Autistic Children

The autism behavior checklist (ABC) has potential utility for evaluation of autistic children in resource-poor settings. Although the original total cutoff score has been described as 67, lower cutoffs have been suggested. We evaluated the sensitivity of ABC in the diagnosis of autism in Indian children. This study was conducted over 2 years in the Child Development Clinic of a tertiary care hospital. Children diagnosed with autistic disorder as per the DSM-IV criteria were included. Children with comorbid motor, visual, and hearing deficits were excluded. Each child was evaluated using the Childhood Autism Rating Scale and ABC. Fifty-one children were enrolled in the study. The mean age was 3.28 +/- 1.89 years. The ratio of boys to girls was 2.2:1. The mean Childhood Autism Rating Scale score was 44.7 +/- 6.22, with all children having scores in the autistic range. The mean ABC score was 72.4, with a standard deviation of 14.2. By using the originally suggested cutoff score of 67, only 40 children in this study were diagnosed with autism. When lower cutoffs were used, the sensitivity increased, with a sensitivity of 98% and a cutoff of 45. The ABC cutoff needs to be lowered to increase its sensitivity for diagnosis of autistic disorder.

A Placebo-Controlled, Fixed-Dose Study of Aripiprazole in Children and Adolescents With Irritability Associated With Autistic Disorder

ObjectiveTo evaluate the short-term efficacy and safety of aripiprazole in the treatment of irritability in children and adolescents with autistic disorder. MethodTwo hundred eighteen children and adolescents (aged 6–17 years) with a diagnosis of autistic disorder, and with behaviors such as tantrums, aggression, self-injurious behavior, or a combination of these symptoms, were randomized 1:1:1:1 to aripiprazole (5, 10, or 15 mg/day) or placebo in this 8-week double-blind, randomized, placebo-controlled, parallel-group study. Efficacy was evaluated using the caregiver-rated Aberrant Behavior Checklist Irritability subscale (primary efficacy measure) and the clinician-rated Clinical Global Impressions–Improvement score. Safety and tolerability were also assessed. ResultsAt week 8, all aripiprazole doses produced significantly greater improvement than placebo in mean Aberrant Behavior Checklist Irritability subscale scores (5 mg/day, −12.4; 10 mg/day, −13.2; 15 mg/day, −14.4; versus placebo, −8.4; all p < .05). All aripiprazole doses demonstrated significantly greater im provements in mean Clinical Global Impressions–Improvement score than placebo at week 8. Discontinuation rates due to adverse events were as follows: placebo 7.7%, aripiprazole 5 mg/day 9.4%, 10 mg/day 13.6%, and 15 mg/day 7.4%. The most common adverse event leading to discontinuation was sedation. There were two serious adverse events: presyncope (5 mg/day) and aggression (10 mg/day). At week 8, mean weight change (last observation carried forward) was as follows: placebo +0.3 kg, aripiprazole 5 mg/day +1.3 kg, 10 mg/day +1.3 kg, and 15 mg/day +1.5 kg; all p < .05 versus placebo. ConclusionsAripiprazole was efficacious and generally safe and well tolerated in the treatment of children and adol escents with irritability associated with autistic disorder. J. Am. Acad. Child Adolesc. Psychiatry, 2009;48(11):1110–1119.

Anxiety and avoidance in infants and toddlers with autism spectrum disorders: Evidence for differing symptom severity and presentation

Little is known about the symptoms of anxiety in very young children with autism spectrum disorders, particularly comparisons between Autistic Disorder (AD) and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS). In the current study, toddlers (i.e., 17–37 months of age) with diagnoses of either AD ( N = 159) or PDD-NOS ( N = 154) were compared to atypically developing toddlers who did not meet criteria for an autism spectrum disorder ( N = 200). Results indicated an overall pattern whereby toddlers with AD had more severe anxious and avoidant symptoms than either toddlers with PDD-NOS or controls. Further, toddlers with PDD-NOS were significantly more severe than controls. Additional analyses examining specific differences between the groups on anxious and avoidant items were conducted as well. Overall, toddlers with AD appear to have more severe anxiety than either those with PDD-NOS or controls, who did not differ on many items.

Autism in children and adolescents with cancer

The causes of autistic disorders (AD) are not known. Abnormalities of tumor suppressor genes have suggested that these genes may be important to the development of autism in some cases, and result in an increased risk of developing cancer or other neoplasms. We explore possible associations between AD and childhood cancer. We reviewed our institutional pediatric cancer database for all new cancer diagnoses 1997-2007. Medical records from patients older than 2 years at last visit were reviewed for a diagnosis of AD. The prevalence of AD was estimated for neoplasms overall and for specific tumor types, and compared with that in the general pediatric population. Of 702 eligible patients, 7 (1%; 95% CI: (0.4%, 2.04%)) were labeled as AD, not different than the prevalence of AD in North Carolina's general population (0.65%, P = 0.35). Cancer diagnoses for these 7 children were acute lymphoblastic leukemia (n = 1), acute nonlymphocytic leukemia (n = 2), non-Hodgkin lymphoma (n = 1), Hodgkin Disease (n = 1), brain tumor (n = 1), osteogenic sarcoma (n = 1). These data do not suggest that there is a high concordance between AD and childhood cancer. However, studies of large rigorously characterized AD cohorts will be needed to definitively address this issue.

The Conceptual Development of DSM-V

The Conceptual Development of DSM-V

Co-occurrence of X-Linked Congenital Adrenal Hypoplasia and Autistic Disorder

Back to table of contents Previous article Next article LETTERFull AccessCo-occurrence of X-Linked Congenital Adrenal Hypoplasia and Autistic DisorderKarl G. Sieg M.D.,Karl G. Sieg M.D.Search for more papers by this author,Published Online:1 Apr 2009AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: One form of congenital adrenal hypoplasia is associated with the Xp21 chromosomal region. These patients have clinical abnormalities including mental retardation, hearing loss, hypogonadism, glycerol kinase deficiency, ornithine transcarbamoylase deficiency, and Duchenne muscular dystrophy. This letter presents a case of a patient with X-linked congenital adrenal hypoplasia whose mental status as a preadolescent male was also consistent with the diagnosis of autistic disorder. Case ReportA 12-year-old Caucasian boy presented with features of autistic disorder including marked lack of awareness of the feelings of others; no seeking of comfort in times of distress; gross impairment in ability to make peer friendships; abnormal nonverbal communication; abnormalities in speech production including perseveration and echolalia; stereotyped body movements including flapping, clapping, and rocking; and persistent preoccupation with parts of objects reflecting a restricted range of interests. His Autism Behavior Checklist total score was 126 with the following subscale profile results: sensory 15, relating 33, body and object use 31, language 25, social and self-help 22. Speech and language testing indicated an age equivalency of 2.8 to 3.0 years old with severe delays of receptive and expressive language as well as speech articulation. MRI brain scan was unremarkable. Chromosomal analysis had confirmed a deletion at the Xp21 region. His family pedigree noted several female congenital adrenal hypoplasia carriers including his mother as well as male infants who had died from congenital adrenal hypoplasia with no family history of autism, nor other developmental, neurologic, or psychiatric conditions. The patient had been prenatally diagnosed with congenital adrenal hypoplasia and survived with in utero replacement therapy initiated at 40 weeks gestation with 100 mg of dehydroepiandrosterone sulfate infused into the amniotic space. Subsequent assessments revealed normalizing maternal estriol excretion. After birth at 43.5 weeks gestation, mineralocorticoid replacement therapy was administered during infancy. Later evaluations revealed steroid deficiencies as well as chronic failure to thrive. Progressive motor, language, and socialization delays followed as described.Comment Despite receiving replacement treatment, it is conceivable that congenital adrenal hypoplasia-related neurophysiologic abnormalities may have already been staged. Adrenal hormone imbalances have been linked to disturbances of development, language, memory, and mood. 1 Congenital adrenal hypoplasia can impact the function of the mineralocorticoid and glucocorticoid receptor systems for cortisol binding in the limbic system. The mineralocorticoid receptors, located in the lateral septum and hippocampus, affect tonic influences on brain function. 2 They demonstrate a 10-fold higher binding affinity for cortisol over glucocorticoid receptors. 1 Glucocorticoid receptors are more widely distributed in the lateral septum, central amygdala, locus coeruleus, and dentate nucleus having involvement with feedback action on stress-activated brain mechanisms. 2 Other studies demonstrated the selective loss of hippocampal granule cells after adrenalectomy suggesting adrenal hormones are a requirement for limbic structural integrity. 3 Adrenal deficiency causes hippocampal serotonin receptor density to selectively increase along with development of subsensitivity at presynaptic receptors. 4 Such impacts on serotonin receptors are particularly significant as alterations of serotonergic neurotransmission have been implicated in both autistic disorder and mental retardation. 5La Amistad Behavioral Health Services, Maitland, Florida

Effectiveness of Mirtazapine in the Treatment of Inappropriate Sexual Behaviors in Individuals with Autistic Disorder

The aim of this study was to investigate the efficacy and safety of mirtazapine in the treatment of excessive masturbation and other inappropriate sexual behaviors (ISB) in individuals with the diagnosis of autistic disorder (AD). Subjects (n = 10; 2 females, 8 males; age range: 5.2-16.4 years) who suffered from excessive masturbation with or without other ISB were treated with mirtazapine for 8 weeks. Clinical Global Impressions-Severity (CGI-S) and Clinical Global Impressions-Improvement (CGI-I) scales were used for the evaluation of symptoms severity and effectiveness. Mirtazapine was started at 7.5-15 mg/day and titrated up to 15-30 mg/day (mean 21.6 +/- 7.9 mg/day). The data for this study were collected from reviewing medical records of all subjects that suffered from ISB and treated with mirtazapine. CGI scores at baseline and end point ranged from 5 to 7 (mean 6.22 +/- 0.83) and 2 to 4 (mean 3 +/- 0.7), respectively. A nonparametric t-test showed significant difference in CGI-S scores between baseline and end point assessments (Z = -2.725; p = 0.006, p < 0.01). Five subjects showed very much, 3 showed much, and 1 showed moderate improvement in excessive masturbation on the CGI-I scale. One subject dropped out from clinical follow up. Mirtazapine was generally tolerated well. The most frequently reported side effects were increased appetite, weight gain (n = 3; mean 0.78 +/- 1.20 kg), and sedation. Mirtazapine could be an effective treatment to ameliorate ISB in a young population with a diagnosis of AD. Well-designed, placebo-controlled studies are needed regarding this topic.

Pervasive developmental disorders in individuals with cerebral palsy

The aim of the present study was to describe the prevalence and associated factors of pervasive developmental disorders (PDD), including autistic disorder and PDD not otherwise specified (NOS), in a clinical sample of 126 children and adolescents (75 males, 51 females; age range 4-18y, mean 8y 8mo, SD 3y 8mo) with tetraplegic, hemiplegic, diplegic, dyskinetic, or mixed types of cerebral palsy (CP); 28% could not crawl or walk even with support, 29% could move with support, and 43% walked independently. Participants were examined for PDD in two stages. In the first stage, probable participants were determined by direct observation, Autism Behavior Checklist score, and medical reports. In the second stage, those with 'probable' symptoms underwent psychiatric examination and their autistic symptoms were scored on the Childhood Autism Rating Scale. The final diagnosis of autistic disorder or PDD-NOS was given according to DSM-IV criteria. Fourteen (11%) and five (4%) of the participants met the criteria for autistic disorder and PDD-NOS respectively. Children with CP and PDD differed from those without PDD in terms of type of CP (p=0.02), presence of epilepsy (p<0.001), intellectual level (p<0.001), and level of speech (p<0.001). PDD was more common in children with tetraplegic, mixed, and hemiplegic CP, and in children with epilepsy, learning disability, and low level of speech. The findings corroborate the notion that CP is a complex disorder, often associated with additional impairments. PDD is not rare in CP and should be considered in patients with comorbid conditions such as epilepsy, learning disability, and language delay and in the presence of tetraplegic, mixed, and hemiplegic CP types.

Subtypes of Language Disorders in School-Age Children With Autism

Cluster analysis of test scores on expressive phonology and comprehension of words and sentences in 7–9-year-old children with preschool diagnosis of Autistic Disorder yielded 4 clusters. Cluster 1 (N = 11): phonology and comprehension both low; Cluster 2 (N = 4): phonology low, near average comprehension; Cluster 3 (N = 40): average phonology, comprehension low to low average; Cluster 4 (N = 7): average or better phonology and comprehension. The clusters support two major types of language disorders in autism driven by impaired expressive phonology, each divisible by comprehension ability. The clusters refute a single language disorder in autism and are consonant with earlier-defined clinical subtypes.

Using the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule-Generic for the Diagnosis of Autism Spectrum Disorders in a Greek Sample with a Wide Range of Intellectual Abilities

We studied the interrelationship between the Autism Diagnostic Observation Schedule-Generic (ADOS-G), the Autism Diagnostic Interview-Revised (ADI-R) and DSM-IV clinical diagnosis, in a Greek sample of 77 children and adolescents, referred for the assessment of a possible pervasive developmental disorder (PDD) and presenting a wide range of cognitive abilities. The agreement of the ADOS-G and the ADI-R with the clinical diagnosis was estimated as satisfactory and moderate, respectively, while both instruments presented with excellent sensitivity for the diagnosis of autistic disorder along with satisfactory specificity. ADOS-G/ADI-R agreement was estimated as fair. Our results confirm the discriminant validity of ADI-R and ADOS-G in diagnosing pervasive developmental disorders in children and adolescents with a wide range of intellectual abilities.