BackgroundA warm handoff from a physician to a mental health provider is often patients’ first contact with psychological services and provides a unique opportunity for improving treatment engagement in integrated primary care (IPC) settings.ObjectiveIn light of the COVID-19 pandemic, this study sought to examine the impact of different types of telehealth mental health referrals on both the anticipated likelihood of accepting treatment services and anticipated likelihood of continued treatment engagement.MethodsA convenience sample of young adults (N=560) was randomized to view 1 of 3 video vignettes: warm handoff in IPC, referral as usual (RAU) in IPC, or RAU in standard primary care.ResultsLogistic associations between referral type and the likelihood of referral acceptance (χ21=10.9,P=.004) and the likelihood of continued engagement (χ21=32.6,P<.001) were significant. Participants who received a warm handoff were significantly more likely to anticipate both accepting the referral (b=0.35;P=.002; odds ratio 1.42, 95% CI 1.15-1.77) and engaging in continued treatment (b=0.62;P<.001; odds ratio 1.87, 95% CI 1.49-2.34) compared with those who received RAU in the standard primary care condition. Furthermore, 77.9% (436/560) of the sample indicated that they would be at least somewhat likely to access IPC mental health services for their own mental health concerns if they were readily available in their own primary care physician’s office.ConclusionsA telehealth warm handoff resulted in the increased anticipated likelihood of both initial and continued engagement in mental health treatment. A telehealth warm handoff may have utility in fostering the uptake of mental health treatment. Nonetheless, a longitudinal assessment in a primary care clinic of the utility of a warm handoff for fostering referral acceptance and continued treatment engagement is needed to hone the adoptability of a warm handoff process and demonstrate practical evidence of effectiveness. The optimization of a warm handoff would also benefit from additional studies examining patient and provider perspectives about the factors affecting treatment engagement in IPC settings.