A comparison of customized GPTs and GPT-4o for self-medication knowledge: A feasibility study using the Japanese...

This feasibility study aimed to assess whether minimally customized large language models (LLMs) can achieve knowledge levels relevant for self-medication support by evaluating their performance on the Japanese Registered Salesperson Examination. Registered salespersons provide consumers with guidance on appropriate selection and safe use of over-the-counter drugs in Japan. We explored whether LLMs customized through simple reference materials upload, without requiring programming skills or advanced prompt engineering, could achieve comparable knowledge levels.

We used the 2024 Registered Salesperson Examination in Japan as a benchmark dataset, comprising 838 text-only multiple-choice questions across five domains. We created customized GPTs by uploading the official guide for examination question development as a PDF file to GPT-4o, without additional prompts or instructions. Both GPT-4o and the customized GPTs were evaluated using a zero-shot approach with web-browsing capabilities disabled.

The overall accuracy was 78.40% for GPT-4o and 92.36% for the GPTs, with this difference being statistically significant (p < 0.001). The GPTs significantly outperformed GPT-4o across all five domains (p < 0.05).

This feasibility study demonstrates that minimal customization through reference materials upload can achieve performance improvements on knowledge-based assessments. However, examination performance represents only an indirect indicator of knowledge for self-medication support. Future research should evaluate LLMs performance in real-world case scenarios and assess practical utility and safety before implementation in consumer self-medication settings.