<h3>Introduction</h3> We are living in a global pandemic of SARS-CoV-2 (COVID-19) that has infected over 63 million people across the world to date. Even though social-distancing is recommended as a key method of reducing risk, such measures disproportionately impact older adults (OA) whose social contacts are often outside their home. Thus, it is both timely and critical to examine the impact of pandemic-related social isolation on OA's mental health. Also, it is unclear whether OAs experiencing depressive symptoms have increased risk of being adversely impacted by social isolation. The current ongoing study utilizes a combination of remotely conducted interviews and online questionnaires to investigate how OA's mental health has been impacted by pandemic-related social isolation. We present preliminary findings from the first wave of our study. We hypothesized that OAs who report higher degrees of reduced quality and frequency in social relationships and communication will be at greater risk of depression, anxiety, and loneliness. Furthermore, we predicted that OAs who endorse depressive symptoms in the recent past will show a stronger association between adverse changes resulting from limited social activity and mental health. <h3>Methods</h3> We recruited 143 OA participants aged 55 years or older (Mean age=64.9, SD=5.3, 87% female). Prospective participants were excluded for self-reported history of neurological disorders, cognitive impairment, or changes in dosage of any psychotropic medications within the past 4 weeks. Otherwise, individuals with current and/or past history of depression or anxiety were included. Following informed consent, participants were screened for cognitive impairment using the MoCA-mini. Participants then filled out a series of questionnaires related to a self-reported diagnostic screen (SAGE-SR), current symptoms of stress (Perceived Stress Scale), depression (Center for Epidemiologic Studies Depression Scale), anxiety (Geriatric Anxiety Scale), loneliness (UCLA-Loneliness), perceived social support (Multidimensional Scale of Perceived Social Support), and perceived social contribution (Social Contribution subscale of the Social Well-being scale). Moreover, we obtained participants' self-reported appraisal regarding the magnitude of adverse impact caused by COVID-19 pandemic-related social isolation on the quality of their personal social relationships and communication frequency with their loved ones. <h3>Results</h3> Overall, participants who reported greater detriment to social relationships and communication frequency also indicated higher degrees of depressive symptoms (r=.32, p<.001), and loneliness (r=.26, p<.005). Interestingly, frequency of using remote forms of communication with friends and family outside the home were inversely related to pathological mental health symptoms. In other words, those who report frequently keeping in touch with loved ones outside their homes also indicated having lower symptoms of depression (r=-.18, p<.05), anxiety (r=-.18, p<.05), and loneliness (r=-.24, p<.005). Notably, household size was not predictive of the above-mentioned symptoms, but was predictive of stress, such that greater household size was associated with higher levels of stress (r=.21, p<.05). We then separately examined two groups of OAs – those who reported having experienced at least some DSM-5 depressive disorders symptoms in the past 30 days, and those who did not. Self-reported magnitude of pandemic-related detriment to social behavior significantly predicted the severity of loneliness, but only in OAs who report some depressive disorder symptoms (r=.24, p<.05). Similarly, in this group, lower perceived social support significantly predicted higher stress (r=-.46, p<.0001) and lower self-reported social contribution predicted higher loneliness (r=-.33, p<.01) respectively. <h3>Conclusions</h3> The preliminary data from our study suggest that greater levels of pandemic-related social isolation are associated with higher severity of symptoms of depression, anxiety, and loneliness. Importantly, OAs with depressive symptoms appear to be at risk of adversely being impacted by loss of social support and absence of meaningful outlet for social contributions during prolonged social isolation. Conversely, our data suggest utilizing psychosocial interventions designed to shore up social support and greater agency in social contribution may be particularly beneficial to OAs who experience depressive symptoms. The correlational nature of our current data is a limitation that will be addressed by our future work gathering responses from the same group of participants who are expected to resume social activity outside the context of pandemic-related social isolation (i.e., Wave 2). Our future work will also address how social isolation relates to day-to-day experience and control of emotions, which is a significant dimensional predictor of functional impairment and distress across multiple psychopathologies. <h3>Funding</h3> Funding <i>support from</i> <b>Special Emphasis: Emerging COVID-19/SARS-CoV-2 Research</b> seed grant awarded to J. Kim, <i>through the Immunology, Inflammation and Infectious Diseases Initiative</i> and the Office of the Vice President for Research at the University of Utah