cVEDA

c-VEDA is a multi-site cohort in India that follows children, adolescents and young adults to study how environmental exposures and genes shape brain development and the risk of externalizing disorders, substance misuse and other mental health problems. It is run jointly by NIMHANS in Bengaluru and King's College London, funded by the Indian Council of Medical Research and the UK Medical Research Council, and its protocols were aligned with IMAGEN. The dataset is released in numbered versions with DOIs; 1.5 (June 2021) is the latest listed.

Composition

Baseline assessments of 9,010 participants took place between November 2016 and May 2019 at seven recruitment centres in Chandigarh, Imphal, Kolkata, Rishi Valley, Mysuru and two in Bengaluru. Participants fall into three age bands: 6 to 11, 12 to 17 and 18 to 23 years. The design is an accelerated cohort with planned missingness: each participant is randomised to one follow-up, either one or two years after baseline. A subsample of 1,278 underwent MRI. Besides imaging, the release holds questionnaires on environment, adversity, temperament, parenting and substance use, psychiatric interviews (MINI), neuropsychological tasks, anthropometry, genotypes and toxicology from blood and urine.

Acquisition

Six of the seven sites contributed MRI participants, scanned at four centres on five 3T systems (Siemens Verio, Trio and Skyra; Philips Ingenia). The protocol, matched to IMAGEN, has a 3D T1w MPRAGE, resting-state fMRI, a B0 map where the scanner offers one, diffusion with a reversed phase-encoding acquisition, 2D FLAIR and 2D T2w. Neuroimaging participants were invited for a repeat scan at follow-up. Phantom scans, regular scans of healthy volunteers and an automated check after each scan were used for quality control.

Known limitations

• Recruitment used convenience sampling in schools, colleges, communities and clinics, so the cohort does not represent the Indian population.
• MRI consent was lower in the youngest age band, and follow-up rates in the imaging subsample were low, especially among younger children.
• The release notes list participant identifiers that appear in the questionnaire files but not in the recruitment files, and the reverse.
• The original project domain cveda.org no longer belongs to the consortium; the website moved to cveda-project.org.