Each caregiver participant will have data collected prior to the recipient s HSCT (day 0), during the first week of outpatient visits following the recipient s initial discharge from the inpatient setting, and finally 6 weeks post the transplant recipients initial discharge from the hospital. Questionnaires will capture the psychological and behavioral outcomes and include: Caregiver Reaction Assessment (caregivers only), Health-Promoting Lifestyle Profile II, Perceived Stress Scale, The UCLA Loneliness Scale (Version 3), General Self-Efficacy Scale, and PROMIS Short Forms for Anxiety, Depression, Sleep disturbance and Fatigue. Clinical variables (e.g. vital signs) and physiological variables (e.g. cortisol) will be collected along with the questionnaires during the clinic visit and following history and physical exam by a Licensed Independent Practitioner (LIP). A sample of non-caregivers will be minimally matched for age, gender, and race/ethnicity, and complete all study procedures except the questionnaires that are specific to the caregiver s experience (e.g. caregiver burden). There will be no long term follow-up after the study participation period. Exploratory, hypothesis generating analyses will be performed using parametric and non-parametric techniques.