Psychological predictors of chemotherapy-induced nausea in women with breast cancer: Expectancies and perceived susceptibility.

Objective: Chemotherapy-induced nausea is challenging to predict and treat. Research indicates that pretreatment psychological variables including patients' perceptions of their susceptibility to nausea, expectancies of treatment-related nausea and nausea history (i.e., motion sickness, morning sickness and baseline levels of nausea) may aid in predicting nausea severity during chemotherapy. However, this research is dated and limited in quantity. We investigated whether psychological variables could improve prediction of nausea severity to inform interventions targeting chemotherapy-induced nausea.

Methods: In this secondary analysis, a subgroup of women receiving chemotherapy (for the first time) for breast cancer completed pretreatment measures: perceived nausea susceptibility, nausea expectancies, nausea history and baseline nausea. They rated subsequent nausea severity across 4-days, during treatment and posttreatment in a self-report diary. Structural Equation Modelling was used to explore associations.

Results: Across the women (N = 481), perceived nausea susceptibility predicted subsequent nausea severity (β = 0.16), but nausea expectancies did not (β = 0.05). Nausea history variables demonstrated small-moderate associations with perceived susceptibility (β = 0.21-0.32) and negligible-small associations with nausea expectancies (β = 0.07-0.14).

Conclusion: Perceived nausea susceptibility appears to capture patients' nausea history, to a degree, and is related to nausea severity during treatment. This is an important variable to include in pretreatment prediction of patients at risk of severe nausea.