Conceptual Framework
The Shape-Shifter Model is a biobehavioral approach to guide the biopsychosocial research of symptoms.15 Based on this model, independent and dependent variables (determinants and phenomena, respectively) can change positions in an association, creating bi-directionality and potentially increased explanatory power in the study of associations between biologic or psychologic/behavioral factors and a symptom.15 The variables of study in this review are posture, depression/mood, and QOL.