Abstract
OBJECTIVE: Test whether three mediating processes of Self-Determination Theory are involved in intervention effects on quality of life for breast cancer patients. METHODS: A randomized clinical trial recruited newly diagnosed breast cancer patients for 6 months of (1) Internet training and access, (2) access to an integrated eHealth system for breast cancer (CHESS), (3) a series of phone conversations with a Human Cancer Information Mentor, or (4) both (2) and (3). RESULTS: This paper reports results after the initial 6 weeks of intervention, at which point patients in the combined condition had higher quality of life scores than those in the other three conditions. All three Self-Determination Theory constructs (autonomy, competence, and relatedness) mediated that effect as hypothesized. In addition, the single-intervention groups were superior to the Internet-only group on relatedness, though perhaps this was too soon for that to carry through to quality of life as well. CONCLUSIONS: The SDT constructs do mediate these interventions' effects. PRACTICE IMPLICATIONS: Intervention design can profitably focus on enhancing autonomy, competence and relatedness.