The COVID-19 pandemic has had a pervasive negative impact on mental wellbeing. Symptoms of depression and anxiety increased globally during the pandemic (Daniali et al., 2023; World Health Organization, 2022), and issues such as loneliness and lack of social support have received increased attention. Prior to the pandemic, loneliness already presented as a growing public health issue, with about half of U.S. adults endorsing experiencing loneliness (Cigna, 2020). A myriad of factors during the COVID-19 pandemic could have exacerbated existing concerns, including the social distancing measures and lockdowns imposed during the initial phase of the pandemic (Killgore et al., 2021; Schmits and Glowacz, 2022), as well as the adverse effects of COVID-related stressors on health and wellbeing (Graupensperger et al., 2022; Luk et al., 2023a, Luk et al., 2023b). The gravity of this public health issue and the need for immediate action are evident through the advisory released in May 2023 by U.S. Surgeon General Dr. Vivek Murthy: “Our Epidemic of Loneliness and Isolation.” This advisory warns of the detrimental mental and physical health consequences of loneliness, including increased risk of anxiety, depression, heart disease, stroke, and dementia, and the need to build social connections to combat these risks (Office of the U.S. Surgeon General, 2023).

Research aimed at understanding changes in loneliness from before to during the pandemic is varied. Several studies report that levels of loneliness remained stable (Luchetti et al., 2020; Peng and Roth, 2022), whereas some report an increase (Kovacs et al., 2021; Lee et al., 2020; Macdonald and Hülür, 2021), and others a decrease (Bartrés-Faz et al., 2021). A recent meta-analytic review found an overall increase in loneliness from before to during the start of the pandemic, though the observed effects were small and heterogeneous (Ernst et al., 2022). This heterogeneity illustrates that certain populations may be more vulnerable to experiencing loneliness during the pandemic. For instance, adults who are younger or single, and individuals with lower household incomes or smaller social networks may be at heightened risk for loneliness (Bu et al., 2020; Rumas et al., 2021; Tutzer et al., 2021). Individuals with alcohol use disorder (AUD) are often socially marginalized due to stigma related to alcohol misuse (Room, 2005). These individuals have been identified as a vulnerable group disproportionately affected by the COVID-19 pandemic, as disruptions to AUD treatment and recovery support groups may have increased the likelihood of a relapse and associated medical complications (Murthy and Narasimha, 2021; Perumalswami et al., 2023; Yazdi et al., 2020). In one study, Lommer et al. (2022) investigated changes in loneliness among individuals with substance use across five months of the pandemic, finding that individuals with substance use disorders (SUD) experienced comparable levels of “severe loneliness” to individuals without SUD at baseline, but significantly more “severe loneliness” at the follow-up timepoint. Few investigations, however, have specifically studied changes in loneliness based on individuals’ history of AUD. This is of particular importance considering that loneliness has been associated with increased psychological distress (Horigian et al., 2021) and hazardous alcohol use during the pandemic (Wakabayashi et al., 2022).

As normal social contacts and interactions may have been disrupted during the COVID-19 pandemic (Freedman et al., 2022; Lee et al., 2022), it is critical to understand if access to social support has changed in tandem with these disruptions. Social support refers to tangible support made available within an individual's social network and is a resilience factor that protects individuals from mental health problems (Laham et al., 2021). Research indicates that greater social support was associated with more positive mental health during the pandemic (Szkody et al., 2021; van den Berg et al., 2021). In terms of change over time, one study revealed stability in social support among the French general population during the pandemic (Laham et al., 2021), whereas other studies indicated an increase in social support among older US adults (Ang, 2022) and Chinese adults (Xu et al., 2020). Lommer et al. (2022) found that social support did not change significantly across five months of the pandemic, but that individuals without SUD reported higher perceived social support than those with SUD. Limited research has explored changes in social support according to individuals’ history of AUD and treatment status.

A history of AUD is associated with higher levels of anxiety and depressive symptoms (Lasserre et al., 2022; Ummels et al., 2022), but the mechanisms are unclear. Loneliness is a significant mediator that links various risk factors to mental health outcomes. For instance, loneliness mediated the associations of childhood trauma with adulthood psychopathology (Shevlin et al., 2015). Among college students, loneliness mediated the associations of low social skills with depression and anxiety (Moeller and Seehuus, 2019). Among older adults, loneliness mediated the associations of social and physical environment with mental health (Domènech-Abella et al., 2021). In a sample of healthcare students in Ecuador, loneliness was a mediator of the associations between psychological stress and mental health symptoms during the COVID-19 pandemic (Bonilla-Sierra et al., 2021). Several studies that examined loneliness and pandemic mental health also examined the role of social support as a protective factor (Bareket-Bojmel et al., 2021; Bentley et al., 2022; Pineda et al., 2022; Saltzman et al., 2020). Based on these prior studies, loneliness and social support are potential mediators of the AUD-mental health associations.

The current study had two complementary goals. First, extending a prior study examining the impact of AUD diagnosis and treatment history (AUD-treatment history) on alcohol-related and quality of life outcomes (Luk et al., 2023a), we examined group-specific changes in loneliness, social support, anxiety symptoms, and depression symptoms from before the COVID-19 pandemic to during the pandemic by AUD-treatment history. Second, we tested a mediation model in which loneliness and social support were conceptualized as mediators of the associations between AUD-treatment history and mental health symptoms. In terms of changes over time, we hypothesized an increase in loneliness, a decrease in social support, and increases in anxiety and depressive symptoms. In terms of mediational pathways, we hypothesized that individuals with a history of AUD would report higher loneliness and lower social support, which would in turn be linked to higher anxiety and depressive symptoms.