Seeking a pot of gold with integrated behavior therapy and research to improve health equity: insights from the RAINBOW trial for obesity and depression

More than one third of adults in the United States (U.S.) live with multiple chronic conditions that affect their physical and mental health, functional outcomes, independence, and mortality. The COVID-19 pandemic has exposed not only an increased risk for infection, morbidity, and mortality among those with chronic conditions but long-standing health inequities by age, race, sex, and other social determinants. Obesity plus depression represent one such prevalent comorbidity for which few effective integrated interventions exist, prompting concern about the potential for secondary physical and mental health pandemics post COVID-19. Translational behavioral medicine research can play an important role in studying integrated collaborative healthcare approaches and advancing scientific understanding on how to engage and more effectively treat diverse populations with physical and mental health comorbidities. The RAINBOW (Research Aimed at Improving Both Mood and Weight) clinical trial experience offers a wealth of insights into the potential of collaborative care interventions to advance behavior therapy research and practice. Primary care patients with co-occurring obesity and depression were assigned to either Integrated Coaching for Mood and Weight (I-CARE), which blended Group Lifestyle Balance (GLB) for weight management and the Program to Encourage Active Rewarding Lives (PEARLS) for depression, or usual care, to examine clinical, cost-effectiveness, and implementation outcomes. This commentary highlights the empirical findings of eight RAINBOW research papers and discusses implications for future studies, including their relevance in the U.S. COVID-19 context. Organized by key principles of translational behavioral medicine research, the commentary aims to examine and embrace the heterogeneity of baseline and intervention response differences among those living with multiple chronic conditions. We conclude that to prevent health and healthcare disparities from widening further, tailored engagement, dissemination, and implementation strategies and flexible delivery formats are essential to improve treatment access and outcomes among underrepresented populations.