NAPLS 2

The North American Prodrome Longitudinal Study in its second phase (NAPLS 2, funded by the US National Institute of Mental Health in 2008) followed young people aged 12 to 35 who met criteria for a clinical high risk (prodromal) state for psychosis, along with demographically similar healthy controls. The aims were to test a clinical prediction rule for conversion to psychosis and to study neuroanatomical, electrophysiological, cognitive, hormonal and genetic factors around psychosis onset. The study targeted 720 high-risk participants and 240 controls at eight sites. Imaging data are held in the LONI Image and Data Archive and released on application.

Composition

Cannon et al. (2015) report baseline MRI for 62 high-risk participants who later converted to psychosis, 491 high-risk participants who did not convert and 224 controls, 777 people in total. Of these, 35 converters, 239 non-converters and 135 controls had a usable 12-month or conversion follow-up scan. Forsyth et al. (2014) report working memory fMRI from 166 healthy controls. A traveling-subject substudy scanned 8 healthy adults twice on consecutive days at each of the 8 sites in 2011 (128 sessions).

Acquisition

Imaging, cognition, electrophysiology, cortisol and blood draws were planned at baseline, 12 and 24 months, plus a full assessment at conversion. Five sites (UCLA, Emory, Harvard, UNC, Yale) used Siemens Trio 3 T scanners with 12-channel coils, and three (Zucker Hillside, UCSD, Calgary) used GE 3 T scanners with 8-channel coils. Sagittal 3D T1-weighted images (1 x 1 x 1.2 mm) followed the ADNI protocol, MPRAGE on Siemens and IR-SPGR on GE. Sessions also included a T2-weighted EPI reference image and a Sternberg-style verbal working memory BOLD fMRI run of 182 volumes.

Known limitations

• Counts come from analysis papers, not from a release document, so the archived sample may differ.
• Few converters had a follow-up scan before conversion, and many received antipsychotics between scans.
• Sites differed in participant age, sex ratio and ethnicity.
• The archive's data use terms and study description are not public, so permitted uses cannot be checked before applying.