Purpose: This study aimed to test a structural model examining the relationship between intolerance of uncertainty and mental health symptoms, with physical vulnerability as a mediator, among female caregivers of patients with Alzheimer’s disease.
Methods: Employing a descriptive-correlational design, the study recruited 320 female caregivers from the Alzheimer’s Association of Tehran in 2020 via convenience sampling. Data were collected using the revised Symptom Checklist (SCL-90-R), the Intolerance of Uncertainty Scale–12 (IUS-12), and the Health-Promoting Lifestyle Profile (HPLP). Data were analyzed using  the SPSS and AMOS software.
Results: The findings indicated that the proposed model had a good fit with the data (χ²=70.87, χ²/df=2.08, CFI=0.987, GFI=0.956, RMSEA=0.076). All direct paths were significant: intolerance of uncertainty to mental health symptoms (β=0.250, P=0.001), physical vulnerability to mental health symptoms (β=0.136, P=0.001), and intolerance of uncertainty to physical vulnerability (β=0.241, P=0.001). The indirect effect of intolerance of uncertainty on mental health symptoms through physical vulnerability was also significant (β=0.118, P=0.001).
Conclusions: The findings suggest that intolerance of uncertainty is directly associated with more severe psychological symptoms in female caregivers of Alzheimer’s patients. Moreover, physical vulnerability serves as a partial mediator in this relationship. This highlights the importance of comprehensive interventions that address both psychological and physical well-being in supportive programs for this population.