Subthreshold Depressed Elders in Congregate Housing

Background and Purpose: Clinically relevant subthreshold depression symptoms are particularly common among older adults, reportedly affecting from 13-40% of elders. Elders in residential care, including various types of congregate housing, are particularly vulnerable to these symptoms. Studies have found subthreshold depression to be associated with significant functional impairments and to increase the risk for future full disorders. Yet, to date, few studies have examined the specific symptoms endorsed by subthreshold elders or the risk factors for subthreshold depression among vulnerable elders. This study examined symptoms of subthreshold depression among older adults in congregate housing, compared with their non-depressed peers, and tested a conceptual model of subthreshold depression. Because research has proposed the idea of late life depression as “depression without sadness,” we hypothesized that subthreshold depression would be characterized and distinguished by low energy, social withdrawal and depletion, rather than negative affect. Based on prior literature, we also hypothesized that risk factors for subthreshold depression would include poorer health and functioning, loneliness and grieving a recent loss.

Methods: Self-administered surveys were followed by a diagnostic interview by telephone to 166 white (77.1%) and African American (22.9%) residents of independent and assisted living apartments from six retirement communities who averaged 82.9 years old. The MINI diagnostic interview determined depression status. The 30-item Geriatric Depression Scale was used to measure symptoms. We also collected demographic and health data and psychosocial variables including measures of grief and loneliness. Chi-square and t-tests identified bivariate differences between the subthreshold and non-depressed groups. Bivariate logistic regression analysis was used to estimate a model of predictors of subthreshold depressed status compared to non-depression.

Results: Forty-six individuals (27.7%) were found to have subthreshold depression, seven suffered from major depression, and the remaining 113 (68%) were non-depressed. The symptoms characterizing subthreshold depression included low energy, difficulty with initiative, irritability, worries about the future, lack of positive affect, and feeling downhearted and blue. The non-depressed group also reported high levels of low energy and difficulty with initiative. Contrary to our hypothesis, negative affect symptoms such as sadness and irritability best discriminated the subthreshold group from the non-depressed. The major risk factors for subthreshold depression in this sample were having less education, income inadequacy, African American race, grieving a recent loss, and social loneliness.

Conclusions and Implications: Subthreshold depression in this group of residents of congregate housing shared symptoms with the depletion experienced by many non-depressed elders, but was further characterized by negative affect and lack of hope for the future. Social factors, such as socioeconomic status and personal losses, constituted greater risks for subthreshold depression than did health and functioning. Evidence of both quantitative and qualitative distinction is emerging for subthreshold depression among older adults. A spectrum or dimensional approach to depression in late life with focused attention on type and severity of symptoms may be preferable to a categorical diagnostic approach for both clinical practice and research.