DISCO: A Decade of Epidemiological Research

Background: The scientific study of autism spectrum disorder (ASD) has recently been slowed up because of widespread and uncritical acceptance of a set of time-consuming prescribed diagnostic instruments with very limited scope, focusing on a narrow phenotype of autism. A belief system has been put in place that autism can only be properly diagnosed and studied if these instruments are used. In the meantime, the DISCO, with a broad view of the autism spectrum, corresponding to what is currently known about the very broad phenotype of ASD has been developed and employed in large-scale epidemiological and clinical studies in the UK, the Netherlands, and, particularly, in Scandinavia.   

Objectives:  To carry out epidemiological studies of (a) children in the Faroe Islands and (b) adults in the UK using the DISCO interview. 

Methods:  In both studies, the DISCO was used at the third phase of the studies, following first stage screening and subsequent assessment of suspected cases. In the Scandinavian sample, all 8-17 year old children in the Faroe Islands, born 1985-1994 were screened through schools and the DISCO used in 41 cases after second phase clinical assessment. The UK study was an epidemiological study of adults. A stratified multi-phase random sample was used in the third national survey of psychiatric morbidity in adults in England in 2007. Second phase clinical assessment was carried out using the Autism Diagnostic Observation Schedule Module 4 (ADOS-4). 

Results: The Scandinavian study reported a prevalence level in the Faroe Island similar to that of other western countries. Results showed that .56 of the population had diagnoses of Childhood Autism, Asperger syndrome or Atypical Autism. Male-female ratio was 6:1. The UK study of adults reported ASD prevalence to be 9.8 per 1000. Prevalence was not related to the respondents’ age but was related to male gender, lack of educational qualifications and to living in social housing. None of the cases identified in the survey had taken part in an autism diagnostic assessment or were known to have an ASD.  

Conclusions: The DISCO is a very useful diagnostic interview for the whole range of ASD and its many associated developmental and neuropsychiatric problems. It is suitable for epidemiological studies of both children and adults.