Conspiracy beliefs and intention to use conventional, complementary and alternative medicines: Two vignette studies.

OBJECTIVE: Conspiracy beliefs (CBs) can have substantial consequences on health behaviours by influencing both conventional and non-conventional medicine uptake. They can target powerful groups (i.e. upward CBs) or powerless groups (i.e. downward CBs). Considering their repercussions in oncology, it appears useful to understand how CBs are related to the intentions to use conventional, complementary and alternative medicines (CAM).

DESIGN AND METHODS: This paper includes two pre-registered online correlational studies on a general French population (Study 1 N = 248, recruited on social media Mage  = 40.07, SDage  = 14.78; 205 women, 41 men and 2 non-binaries; Study 2 N = 313, recruited on social media and Prolific, Mage  = 28.91, SDage  = 9.60; 154 women, 149 men and 10 non-binaries). We investigated the links between generic and chemotherapy-related CBs and intentions to use conventional, complementary and alternative medicines. Study 2 consisted of a conceptual replication of Study 1, considering the orientation of CBs.

RESULTS: Generic CBs and chemotherapy-related CBs appear strongly and positively correlated, negatively correlated with intentions to take conventional medicine and positively with intentions to take CAM. The link between generic CBs and medication intention is fully mediated by chemotherapy-related CBs. When distinguished, upward CBs are a stronger predictor of chemotherapy-related CBs than downward CBs.

CONCLUSIONS: The findings suggest that intentions to use medicine are strongly associated with CBs. This has several important implications for further research and practice, notably on the presence and effects of CBs on medication behaviours in cancer patients.