BACKGROUND/OBJECTIVES: While problem-solving interventions can teach caregivers effective coping skills throughout hospice, the optimal timing for introducing such resources remains unclear. We explored how the timing of a problem-solving intervention impacts its effectiveness for hospice caregivers. RESEARCH DESIGN/METHODS: We conducted a multi-method study analyzing quantitative and qualitative data from a randomized clinical trial of a Problem-solving Intervention to Support Caregivers in End-of-life care Settings (PISCES). Caregivers were randomly assigned to 3 intervention groups: PISCES delivered face-to-face (F2F), PISCES delivered in a hybrid format, and PISCES integrating positive appraisal elements (PISCESplus). We compared the anxiety and depressive symptoms before and after the intervention among 318 caregivers across various stages of hospice. We conducted a content analysis of 45 exit interviews to explore how caregivers perceived PISCES and their hospice experience in relation to its timing. RESULTS: Caregivers' anxiety showed significant pre-post differences regardless of the intervention timing, modality, and components. The impact on depressive symptoms differed: While the PISCES F2F group showed significant changes at all timings, only bereaved caregivers had significant changes in the PISCES Hybrid group (p<
0.001). In the PISCESplus group, caregivers in the midst of hospice and bereaved showed significant changes (p=0.043 and <
0.001, respectively). Three themes emerged from the qualitative analysis: timing for PISCES to be most effective, emotions during various stages of hospice, and the length of PISCES. DISCUSSION/IMPLICATIONS: Strategically integrating PISCES into hospice practice can help alleviate caregivers' distress. More work is needed to improve the real-world applicability of caregiver-focused interventions in hospice.