An Investigation into the Miasmatic Classification of Symptoms in Homeopathy: Development of a Checklist of Secondary Symptoms of Psora by Mixed-Methods Research

In homeopathic philosophy, chronic miasms are considered the fundamental causes of 'true, natural' chronic diseases. Hahnemann classified these into three types: psora, syphilis and sycosis. This project primarily aimed to collect and analyze qualitative experts-derived data to develop a consensus-based checklist of secondary symptoms of psora. The secondary aim was to quantitatively evaluate the checklist through partition clustering for compatibility with Hahnemann's miasmatic classification. This paper reports the development of the psora checklist, with two addenda addressing parallel work on syphilis and sycosis.An exploratory sequential mixed-methods design (qual → QUAN) was used. Key secondary symptoms were identified through a staged qualitative inquiry. Initially, symptoms were conceptualized deductively from the literature. Their salience was then ranked through free-listing by five homeopathy experts; symptoms with salience < 0.1 were excluded. Face validity was assessed. Next, five different experts evaluated item congruence in Delphi rounds to establish content validity. Symptoms with an average congruency percentage (ACP) <80% were removed. Pilot usability testing was completed by 15 end-users.A total of 91 psoric symptoms were conceptualized; 67 remained after free-listing, whereas 17 low-salience symptoms were excluded. Fifty symptoms passed face validation and proceeded to content validation. Eighteen symptoms failed the ACP threshold (<80%), leaving 32 items. Pilot testing produced three iterations, and the final version contained 23 symptoms suitable for large-scale data collection. Similar procedures were followed concurrently for syphilis and sycosis symptom lists.This staged, experts-driven process produced a conceptually and quantitatively supported checklist of secondary psoric symptoms. The checklist demonstrated acceptable salience and content validity, forming a structured basis for future miasm-focused research. Further studies should examine its broader clinical applicability and psychometric performance.