British Autism Study of Infant Siblings (BASIS)

Aims
The British Autism Study of Infant Siblings (BASIS) is a prospective longitudinal study of infants at elevated likelihood for autism in the UK. Using newly developed techniques for studying brain and behaviour in infants, BASIS investigates whether there are any differences in development between infants who have brothers or sisters with autism and those who do not. The study has been extended to include infants at elevated likelihood for ADHD.

Institution
King’s College London; Birkbeck, University of London

Geographic coverage - Nations
England, Scotland, Wales, Nothern Ireland

Geographic coverage - Regions
Nationwide (but control participants mostly recruited from London)

Start date
2006

Catalogue record last updated
10/04/2024

Sample type
Cohort study

Sample details
Participating parents and their children were recruited from a volunteer database at the Birkbeck Centre for Brain and Cognitive Development. Infants could be enrolled in the study if they either had a first degree relative with ASD, a first degree relative with diagnosed or probable ADHD, or no first-degree relatives with either diagnosis. In phases 1 and 2, the children recruited were only at elevated likelihood (EL) for ASD, whilst in phase 3, children are at EL for ASD, ADHD, or both. Phase 3 is known as BASIS-STAARS (STudying Autism and ADHD riskS). Some families have taken part in more than one phase.

Infants were identified as being at EL if they had at least one older sibling with a community clinical diagnosis of autism, which was confirmed based on parent report using the Development and Wellbeing Assessment (DAWBA; Goodman et al., 2000), the Social Communication Questionnaire (SCQ; Berument et al., 1999) or parent confirmed community clinical autism diagnosis. Infants were identified as being at typical likelihood (TL) if they had at least one older sibling with typical development and no known autism in first-degree family members (as confirmed through parent interviews regarding family medical history). In phase 3, children were recruited and identified as being at EL for ADHD if they had either an older sibling or a parent with a diagnosis of ADHD, confirmed through parent report using the Conner's Parent Rating Scale, and Conner's Adult.

Cohort members have been assessed at approximately 1, 5, 8, 14, 24, and 36 months, before being followed up during mid-childhood at approximately age 7 to 11 years. The follow up of children at mid-childhood in phase 1 is known as ‘BASIS-7’, whilst follow up for phases 2 and 3 is known as ‘SuperSTAARS’. Participants are administered a range of experimental, behavioural and cognitive tasks and interactive assessments of autistic symptomatology. Parents also complete a range of questionnaires and interviews relating to different aspects of early development. Phase 1 data collection ran from 2006-2015, phase 2 from 2009-2022, and phase 3 from 2013-2023.

Sample size at recruitment
Phase 1: 104
Phase 2: 143
Phase 3: 300

Sample size at most recent sweep
Phase 1: 76
Phase 2: 97
Phase 3: ongoing

Sex
All

Age at recruitment
Birth (from prenatal to early infancy)

Cohort year of birth
Varied