Neuroimaging & Biosample Collection in the Toronto Adolescent and Youth (TAY) Cohort Study: Rationale, Methods, and Early Data

Background: The Toronto Adolescent and Youth (TAY) Cohort study will characterize the neurobiological trajectories of psychosis spectrum symptoms (PSS), functioning, and suicidality (i.e., suicidal thoughts and behaviors) in youth seeking mental health care. Here, we present the neuroimaging and biosamples component of the protocol. We also present feasibility and quality control (QC) metrics for the baseline sample collected thus far. Methods: The present study includes youth (aged 11-24 years) referred to child and youth mental health services within a large, tertiary care centre in Toronto, Canada, with target recruitment of 1500 participants. Participants were offered the opportunity to provide any or all of a: (i) 1-hour MRI scan (EEG if ineligible or declined MRI), (ii) blood sample for genomic and proteomic data (or saliva if blood collection was declined or not feasible) and urine sample, and (iii) heart rate recording to assess respiratory sinus arrhythmia (RSA) Results: Of the first 417 participants consenting to participate between May 4, 2021 and February 2, 2023, 412 agreed to participate in the Imaging and Biosamples Protocol. Of these, 334 completed imaging, 341 provided a biosample, and 338 completed RSA. 316 completed all three. Following QC, data usability was high (MRI: T1w 99%, DWI 99%, ASL 90%, resting-fMRI 95%, task-fMRI 90%; EEG: 83%; RSA: 99%). Conclusions: The high consent rates, good completion rates, and high data usability reported here demonstrate the feasibility of collecting and utilising brain imaging and biosamples in a large clinical cohort of youth seeking mental health care.