The quality of social relationships is a significant risk factor for major depression, findings from a longitudinal study of more than 4,000 American adults showed.
The estimated risk of developing major depression was 14% for people with poor-quality relationships, compared with 6.7% for people with high-quality relationships.
The nationally representative study by Dr. Alan R. Teo and his associates looked at whether the quality and quantity of social relationships in a community population increased the risk of developing major depression a decade later.
Dr. Teo and his associates conducted surveys at baseline in 1995-1996 and again in 2004-2006 with 4,642 participants aged 25-75. Women made up slightly more than half of the sample, and 92% of the participants were white. Five hundred fifty-nine participants (12.3%) had a major depressive episode at baseline, based on the results of the Composite International Diagnostic Interview Short Form.
The investigators measured social relationship quality at baseline using composite scales that included items of social support and social strain. Social isolation was measured by the presence of a partner and reported frequency of social contact with friends and neighbors and with family members who did not live with the survey participants (PLoS ONE 8:e62396).
Even after accounting for participants with baseline depression, the researchers found that the quality of social relationships predicted future depression. "The results were similar when analyses were restricted to those participants without major depression at baseline, which suggests that the predictive power of social relationship quality is not explained by depression’s influence on self-report of one’s social relationships," wrote Dr. Teo of the department of psychiatry at the University of Michigan, Ann Arbor.
Poor-quality relationships with spouses or partners and, to a lesser extent, with family members, independently increased the risk of depression. "This extends and corroborates earlier cross-sectional research that showed not getting along with one’s spouse was related to more psychiatric disorders than not getting along with relatives or friends," the authors reported.
Contrary to what the researchers expected, social isolation at baseline did not predict the risk of depression or moderate the effect of quality of social relationships on subsequent depression risk.
The authors cited several limitations. Among them is that focusing on only two time periods for analysis with long intervals in between might have opened the possibility for the participants’ quality of social relationships to change. Another limitation was that the analyses lacked specific data to distinguish between incident and recurrent major depression, "though given the age of the participants and the known epidemiology of depression, it is likely that many cases were current," the authors wrote.
Still, the study has important implications for clinicians and public health officials. "Asking patients about their subjective perceptions of their social relationships should be a priority," Dr. Teo and his associates wrote. "Including questions in the clinical encounter about, for instance, how much others understand and care about the patient ... should be considered evidence based, much like inquiring about past depressive episodes."
The study was supported by the Robert Wood Johnson Foundation. The authors reported having no financial conflicts.