Pain‐Related Smoking Expectancies Across Tobacco Product Use Patterns, Including Heated Tobacco Products: Psychometric Validation of the Japanese Pain and Smoking Inventory

AIM: With the rapid proliferation of heated tobacco products (HTPs) in Japan, understanding pain-related smoking expectancies across tobacco use patterns has become increasingly important. In this study, we aimed to profile these expectancies among adults with pain using the Pain and Smoking Inventory (PSI) and to evaluate its psychometric properties in a Japanese context. METHODS: We conducted a cross-sectional internet-based survey in 2024 among 300 Japanese adults with pain who smoked daily. Participants were categorized as combustible-only, HTP-only, switchers (from cigarettes to HTPs), or dual users. Psychometric evaluation included assessment of factor structure, internal consistency, and convergent validity. We used a structural equation model to examine associations between the latent PSI score and pain-related outcomes. We then conducted analyses of covariance to compare PSI scores across tobacco use groups (adjusted for age and gender). RESULTS: Psychometric validation indicated high internal consistency (α = 0.93), mixed but essentially unidimensional fit, and expected correlations with nicotine dependence, pain, and psychological measures. The structural equation model demonstrated significant positive associations between the latent PSI factor and pain intensity (β = 0.29, p < 0.001) as well as pain-related disability (β = 0.39, p < 0.001). Exploratory group comparisons revealed higher PSI scores among dual users than switchers, reflecting stronger perceived pain-smoking relationships. HTP-only users also showed descriptively elevated profiles similar to combustible and dual users. CONCLUSIONS: Pain-related smoking expectancies differed across tobacco product use patterns, with dual users showing higher-risk expectancy profiles. The PSI may serve as a useful tool for screening and tailored intervention in pain and tobacco use contexts.