Broad clinical high-risk mental state (CHARMS): Methodology of a cohort study validating criteria for pluripotent...

The development of the ultra-high risk (UHR) criteria for psychosis created a new paradigm for the prevention research in psychiatry. Since (1) prevention research faces the challenge of achieving adequate statistical power when focusing on single low-incidence syndromes and (2) early clinical phenotypes are overlapping and non-specific, this study broadens the UHR state beyond psychosis as an outcome. The CHARMS (clinical high at-risk mental state) study aims to prospectively validate a set of trans-diagnostic criteria to identify help-seeking young people at risk of developing a range of serious mental illnesses.

This paper describes the methodology of the CHARMS study, which involves applying the CHARMS criteria to a cohort of help-seeking young people aged 12 to 25 attending youth mental health services in Melbourne. New referrals meeting the CHARMS criteria are allocated to the CHARMS+ group; referrals not meeting CHARMS threshold are allocated to CHARMS- group (control group); referrals meeting criteria for a full-threshold disorder are excluded. Transition status and clinical and functional outcomes are re-assessed at 6 and 12 months.

This study will be the first to introduce and validate clinical criteria to identify a broader at-risk patient population, which may facilitate young people's access to clinical services and early treatment by reducing the reliance on "caseness" defined according to current diagnostic categories being required for service entry. These criteria may introduce a new, trans-diagnostic approach for understanding risk factors and pathogenic mechanisms that drive the onset of severe mental illness and the next generation of preventive intervention trials.