Background: The interdependence between patient and caregivers' health, which is when the patients' and informal caregivers' emotion, cognition and/or behavior affects that of the other person is well documented among dyads experiencing cancer and heart disease, but scant research has assessed interdependence among those with brain injuries or dementia and Latina/o populations. This study aimed to assess the interdependence of patient and caregiver depression, patient functional independence and caregiver burden among non-Latina/o and Latina/o and patients with brain injuries and dementia and their caregivers. Methods: Patients and caregiver dyads (n = 96) were recruited from a trauma hospital. Participants completed measures on patient and caregiver depression, patient functional independence and caregiver burden. Participants provided written informed consent. Patient inclusion criteria included: (1) diagnosis with a brain injury or dementia, (2) minimum age of 12, (3) community dwelling and (4) ability to verbally communicate and complete study measures. Caregivers were only included if they were informal, unpaid, family or a friend. Nonparametric Spearman's Rho correlations were conducted to test the study hypotheses. Discussion: There was consistently a statistically significant positive relationship between caregiver depression and caregiver burden for all groups. For non-Latina/o patient and caregiver dementia dyads, there were associations between patient depression and caregiver depression. For non-Latina/o dementia dyads, functional ability was only associated with patient depression. For Latina/o patient and caregiver brain injury and dementia dyads, the only statistically significant relationship was between caregiver depression and caregiver burden. Health services should embrace family-focused mental health and respite interventions.