King's College London

Research portal

Predicting the diagnosis of autism in adults using the Autism-Spectrum Quotient (AQ) questionnaire

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)2595-2604
JournalPsychological medicine
Volume46
Issue number12
Early online date29 Jun 2016
DOIs
StateE-pub ahead of print - 29 Jun 2016

Documents

King's Authors

Abstract

Background: Many adults with autism spectrum disorder (ASD) go undiagnosed. Specialist adult assessment services play a key role in the detection of these cases. However, such services are often overstretched. It is proposed that the Autism-Spectrum Quotient (AQ), a self-report questionnaire measuring autistic traits, could reduce unnecessary referrals if those scoring above a cut-off on the AQ were prioritized for assessment. However, the ability of the AQ to predict who will receive a diagnosis of ASD is unclear.

Method: We studied a consecutive series of 476 adults seen by a national ASD diagnostic referral service on suspicion of ASD. We examined whether AQ scores predicted ASD diagnoses made by clinicians using ICD-10 criteria and informed by the Autism Diagnostic Observation Schedule Generic (ADOS-G) and Autism Diagnostic Interview Revised (ADI-R).

Results: Scores on the self-report AQ did not predict expert clinical diagnosis any better than chance. The AQ showed high sensitivity of 0.77 (95% CI: 0.72-0.82) but low specificity 0.29 (0.20-0.38), and while the Positive Predictive Value (PPV) was high 0.76 (0.70-0.80), the low Negative Predictive Value NPV of 0.36 (0.22-0.40) indicates that nearly two thirds of those who scored below the cut-off were 'false negatives', screening negative but receiving a diagnosis of ASD. A comorbidity analysis revealed that generalized anxiety disorder (GAD) may 'mimic' ASD and inflate AQ scores, leading to false positives.

Conclusions: The AQ has limited utility for screening referrals. Recommendations (e.g. UK guidelines) supporting its role in the assessment of adult ASD may need to be revised.

Download statistics

No data available

View graph of relations

© 2015 King's College London | Strand | London WC2R 2LS | England | United Kingdom | Tel +44 (0)20 7836 5454