Objectives This study aimed to compare the effects of poppy seed oil use with and without education based on Bandura’s social cognitive theory (SCT) on pain severity and pain self-efficacy in older adults with knee osteoarthritis (KO). Pain is the main symptom of older adults with osteoarthritis.
Methods & Materials This is a double-blind randomized controlled clinical trial on 129 older people with KO referred to a pain clinic in Babol city, north of Iran, in 2022-2023. They were divided into three groups, A, B, and C, using the block randomization method. Group A used poppy seed oil consumption along with education based on the SCT model. Group B used poppy seed oil without education, and group C was the control group that received routine treatments. A demographic form, pain self-efficacy questionnaire (PSEQ), and visual analogue scale (VAS) were used to collect data. Data was analyzed in SPSS software, version 23 using the chi-square test, analysis of variance, Friedman’s test, Kruskal-Wallis test, and regression analysis.
Results Most of the participants were female (n=102, 77.9%). No significant difference was observed in the VAS score among the groups from the pretest phase to week 4, from the pretest phase to week 8, or from week 4 to week 8 post-intervention (P>0.05). The mean VAS score in three groups was significantly different among the three time points (P<0.05). The difference in PSEQ score was significant in weeks 4 and 8 post-intervention only between Groups A and C (P=0.004 and 0.001, respectively), but not between groups A and B or between groups B and C (P>0.05). Also, the mean PSEQ score was significantly different among the three time points in Groups A and B (P<0.001). 
Conclusion The use of poppy seed oil with or without SCT-based education can improve pain severity and pain self-efficacy in older adults with KO.