NIMH describes RDoC as a research framework for studying dimensions of functioning across psychological and biological systems. HiTOP is an empirical, hierarchical taxonomy intended to improve the organisation, description and measurement of psychopathology.
RDoC is not a diagnostic manual
NIMH explicitly states that RDoC is not intended to serve as a diagnostic guide or replace current diagnostic systems. Its purpose is research. It examines fundamental systems of functioning across dimensions and across multiple units of analysis.
HiTOP starts from the empirical structure of psychopathology
HiTOP seeks to organise psychopathology using observed patterns of covariation rather than relying only on traditional disorder categories. It is hierarchical, allowing narrower symptom dimensions to sit within broader spectra.
Why they matter to PHCF
Both frameworks show that psychiatric classification is not a closed problem. They also illustrate that different classification questions require different architectures. PHCF does not attempt to reproduce either model. Its question is narrower - whether positive mental health can be organised into a clinically meaningful classification that contributes information beyond disorder, symptoms and functioning.
Where the comparison should stop
RDoC and HiTOP have substantial research programmes and established scientific communities. PHCF is developmental. Any comparison should therefore concern the problem being addressed and the structure proposed, not imply equivalent empirical maturity.