This report, presented in the National Health Statistics Reports, examines the relationship between living alone and feelings of depression among adults aged 18 and older in the United States. Using data from the 2021 National Health Interview Survey (NHIS), the study found that 16.0% of adults lived alone, and those living alone reported higher levels of depression (6.4%) compared to those living with others (4.1%). The differences in depression were observed across various sociodemographic characteristics, including age, sex, race, Hispanic origin, and family income. Adults who lived alone and rarely received social and emotional support were nearly twice as likely to report depression (19.6%) compared to those who lived with others and rarely received support (11.6%). However, no significant differences were found in depression levels among those who sometimes, usually, or always received social and emotional support. The report highlights the potential vulnerability of certain groups, such as adults at midlife, men, Hispanic adults, and those with limited social support, to adverse mental health effects associated with living alone.This report, presented in the National Health Statistics Reports, examines the relationship between living alone and feelings of depression among adults aged 18 and older in the United States. Using data from the 2021 National Health Interview Survey (NHIS), the study found that 16.0% of adults lived alone, and those living alone reported higher levels of depression (6.4%) compared to those living with others (4.1%). The differences in depression were observed across various sociodemographic characteristics, including age, sex, race, Hispanic origin, and family income. Adults who lived alone and rarely received social and emotional support were nearly twice as likely to report depression (19.6%) compared to those who lived with others and rarely received support (11.6%). However, no significant differences were found in depression levels among those who sometimes, usually, or always received social and emotional support. The report highlights the potential vulnerability of certain groups, such as adults at midlife, men, Hispanic adults, and those with limited social support, to adverse mental health effects associated with living alone.