If you do not understand breathing, you should not publish about it: A methodological critique of two studies on light-guided breathing -- and the deeper problem of a profession diagnosing what it cannot measure

Canazei et al. published two studies in 2025 on light-guided slow breathing: one involving hospitalised psychiatric patients (General Psychiatry), the other involving healthy university students performing computer tasks (Computers in Human Behavior Reports). Both studies share the same fundamental methodological failures: heart rate variability is measured during slow breathing and interpreted as a therapeutic effect, although the observed increase is a mechanical artefact of the respiratory frequency itself. Breathing technique is not controlled. Body position is not documented. Light exposure is not separated as a confounder. This paper demonstrates that these are not incidental oversights but symptoms of a structural competence deficit in respiratory mechanics. It further argues that the underlying problem extends beyond methodology: a profession whose diagnostic authority rests on a single consensus-based manual -- the DSM -- presumes expertise in domains such as breathing and light that predate psychology by millennia, while deploying that presumed expertise on vulnerable populations who cannot meaningfully consent to its application. Paradoxically, the research group possesses a genuinely promising therapeutic tool in light -- and misuses it.