Autism phenotype versus registered diagnosis in Swedish children: prevalence trends over 10 years in general population samples

Lundstrom, S., Reichenberg, A., Anckarsater, H., Lichtenstein, P. and Gillberg, C. (2015) Autism phenotype versus registered diagnosis in Swedish children: prevalence trends over 10 years in general population samples. British Medical Journal, 350, h1961. (doi: 10.1136/bmj.h1961) (PMID:25922345) (PMCID:PMC4413835)

Abstract

Objective: To compare the annual prevalence of the autism symptom phenotype and of registered diagnoses for autism spectrum disorder during a 10 year period in children. Design: Population based study. Setting: Child and Adolescent Twin Study and national patient register, Sweden. Participants: 19 993 twins (190 with autism spectrum disorder) and all children (n=1 078 975; 4620 with autism spectrum disorder) born in Sweden over a 10 year period from 1993 to 2002. Main outcome measures: Annual prevalence of the autism symptom phenotype (that is, symptoms on which the diagnostic criteria are based) assessed by a validated parental telephone interview (the Autism-Tics, ADHD and other Comorbidities inventory), and annual prevalence of reported diagnoses of autism spectrum disorder in the national patient register. Results: The annual prevalence of the autism symptom phenotype was stable during the 10 year period (P=0.87 for linear time trend). In contrast, there was a monotonic significant increase in prevalence of registered diagnoses of autism spectrum disorder in the national patient register (P<0.001 for linear trend). Conclusions: The prevalence of the autism symptom phenotype has remained stable in children in Sweden while the official prevalence for registered, clinically diagnosed, autism spectrum disorder has increased substantially. This suggests that administrative changes, affecting the registered prevalence, rather than secular factors affecting the pathogenesis, are important for the increase in reported prevalence of autism spectrum disorder.

• Item Type: Articles
• Additional Information: Funding: The Child and Adolescent Twin Study in Sweden study was supported by the Swedish Council for Working Life, funds under the ALF agreement, the Söderström-Königska Foundation, and the Swedish Research Council (Medicine and SIMSAM). The current study received no specific funding.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gillberg, Professor Christopher
• Authors: Lundstrom, S., Reichenberg, A., Anckarsater, H., Lichtenstein, P., and Gillberg, C.
• College/School: College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Mental Health and Wellbeing
• Journal Name: British Medical Journal
• Publisher: BMJ Publishing Group
• ISSN: 1756-1833
• ISSN (Online): 1756-1833
• Copyright Holders: Copyright © 2015 BMJ Publishing Group
• First Published: First published in BMJ 2015;350:h1961
• Publisher Policy: Reproduced under a creative commons licence