title: Predicting the diagnosis of autism in adults using the Autism-Spectrum Quotient (AQ) questionnaire.
abstract: Many adults with autism spectrum disorder (ASD) remain undiagnosed. Specialist assessment clinics enable the detection of these cases, but such services are often overstretched. It has been proposed that unnecessary referrals to these services could be reduced by prioritizing individuals who score highly on the Autism-Spectrum Quotient (AQ), a self-report questionnaire measure of autistic traits. However, the ability of the AQ to predict who will go on to receive a diagnosis of ASD in adults is unclear.
  
  
  
  We studied 476 adults, seen consecutively at a national ASD diagnostic referral service for suspected ASD. We tested AQ scores as predictors of ASD diagnosis made by expert clinicians according to International Classification of Diseases (ICD)-10 criteria, informed by the Autism Diagnostic Observation Schedule-Generic (ADOS-G) and Autism Diagnostic Interview-Revised (ADI-R) assessments.
  
  
  
  Of the participants, 73% received a clinical diagnosis of ASD. Self-report AQ scores did not significantly predict receipt of a diagnosis. While AQ scores provided high sensitivity of 0.77 [95% confidence interval (CI) 0.72-0.82] and positive predictive value of 0.76 (95% CI 0.70-0.80), the specificity of 0.29 (95% CI 0.20-0.38) and negative predictive value of 0.36 (95% CI 0.22-0.40) were low. Thus, 64% of those who scored below the AQ cut-off were 'false negatives' who did in fact have ASD. Co-morbidity data revealed that generalized anxiety disorder may 'mimic' ASD and inflate AQ scores, leading to false positives.
  
  
  
  The AQ's utility for screening referrals was limited in this sample. Recommendations supporting the AQ's role in the assessment of adult ASD, e.g. UK NICE guidelines, may need to be reconsidered.
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: K L
authors.initials: KL
authors.lastname: Ashwood
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: N
authors.initials: N
authors.lastname: Gillan
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: J
authors.initials: J
authors.lastname: Horder
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: H
authors.initials: H
authors.lastname: Hayward
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: E
authors.initials: E
authors.lastname: Woodhouse
authors.affiliation: South London and Maudsley National Health Service Foundation Trust (SLAM),Maudsley Hospital,London,UK.
authors.forename: F S
authors.initials: FS
authors.lastname: McEwen
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: J
authors.initials: J
authors.lastname: Findon
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: H
authors.initials: H
authors.lastname: Eklund
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: D
authors.initials: D
authors.lastname: Spain
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: C E
authors.initials: CE
authors.lastname: Wilson
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: T
authors.initials: T
authors.lastname: Cadman
authors.affiliation: Centre for Mental Health, Imperial College London,London,UK.
authors.forename: S
authors.initials: S
authors.lastname: Young
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: V
authors.initials: V
authors.lastname: Stoencheva
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Murphy
authors.affiliation: South London and Maudsley National Health Service Foundation Trust (SLAM),Maudsley Hospital,London,UK.
authors.forename: D
authors.initials: D
authors.lastname: Robertson
authors.affiliation: Department of Psychology,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: T
authors.initials: T
authors.lastname: Charman
authors.affiliation: Social, Genetic & Developmental Psychiatry (SGDP) Centre,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: P
authors.initials: P
authors.lastname: Bolton
authors.affiliation: Department of Social Science, Health & Medicine,School of Social Science & Public Policy,King's College London,London,UK.
authors.forename: K
authors.initials: K
authors.lastname: Glaser
authors.affiliation: Social, Genetic & Developmental Psychiatry (SGDP) Centre,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: P
authors.initials: P
authors.lastname: Asherson
authors.affiliation: Child & Adolescent Psychiatry,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: E
authors.initials: E
authors.lastname: Simonoff
authors.affiliation: Department of Forensic and Neurodevelopmental Sciences,Institute of Psychiatry, Psychology & Neuroscience, King's College London,London,UK.
authors.forename: D G
authors.initials: DG
authors.lastname: Murphy
mesh_terms: D000328:Adult; D000067877:Autism Spectrum Disorder / Q000175:diagnosis* / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D057566:Self Report / Q000592:standards*; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult
keywords: Autism; autism spectrum disorders; neurodevelopmental disorders; screening; self-report