Social isolation, particularly from relatives and friends, is correlated both with loneliness and depressive symptoms, a new Singapore study has shown. Moreover, loneliness was also associated with depressive symptoms independent of any social isolation indicator.

“The results of the study establish a significant and unique association of different social isolation indicators and loneliness with depressive symptoms in community-dwelling adults aged 21 and above,” the researchers wrote.

The study drew data from the Population Health Index Survey targeted towards community-dwelling adults in Central Singapore. A total of 1,942 individuals participated in the survey. Only those that were above the age of 21 years and had been in the selected household for at least six months were included.

Social isolation was measured using three indicators: marital status, living arrangement and social connectedness with relatives and friends. Loneliness was assessed with the three-item UCLA Loneliness Scale and depression with the 9-item Patient Health Questionnaire.

Of the participants, 63.8 percent were married, 63.7 percent were employed and 69.8 percent lived with their spouse and/or children. In contrast, 5.0 percent lived alone. A total of 504 (26.3 percent) adults reported being isolated while 22.7 percent had a high risk of isolation. [PLoS One 2017;doi:10.1371/journal.pone.0182145]

A cumulative score of three in the UCLA Loneliness Scale was reported for at least 80 percent of the participants, with 6.4 percent (n=128) who reported feeling lonely. Those who were lonely were more likely to be divorced, unemployed, widowed, have nonmental chronic conditions or previous depression.

Spearman’s rank correlation revealed a weak but significant correlation between loneliness and connectedness with relatives (r, 0.14; p<0.001). By comparison, the association between loneliness and depressive symptoms was stronger (r, 0.32; p<0.001).

Depressive symptom scores were higher in those who were isolated (3.5 vs 1.4) and lonely (5.0 vs 2.0) compared with those at low risk of isolation and who were not lonely, respectively.

“This study disentangles these two aspects of social isolation and examines their associations (together with other social isolation indicators) with depressive symptoms respectively,” said researchers.

Among the strengths of the study are the use of a representative adult population and the examination of different indicators of social isolation and loneliness. Interestingly, the study highlights that social isolation, especially from friends and family, plays a major role in depressive symptoms instead of living arrangement or marital status.

Despite its strengths, the cross-sectional design of the study seriously limits the ability to draw causal relationships from the findings. Follow-ups after one or two years, and future studies that can account for change over time, will be valuable for establishing causation, according to researchers.