Major depression, physical illness, and suicidal ideation in primary care

To determine the association between major depression and suicidal ideation and the role of physical illness in this link among primary care patients.

More than 3,000 randomly selected primary care patients at eight sites across the United States completed the PRIME-MD PHQ, a screen for mental disorders for use in primary care. Physicians independently diagnosed physical illnesses. Multiple logistic regression analyses were used to determine the relationship between PRIME-MD depression, physical illness, and suicidal ideation.

Pulmonary disease was associated with an increased likelihood of suicidal ideation, even among patients without major depression [odds ratio = 1.9 (1.04, 3.4)]. There was evidence of statistical interaction between pulmonary disease and depression in increasing the odds of suicidal ideation. Specifically, patients with pulmonary disease without depression, those with depression without pulmonary disease, and patients with both pulmonary disease and depression had significantly increased odds of suicidal ideation with odd ratios of 1.9 (1.04, 3.4), 7.4 (5.6, 9.7), and 9.6 (5.1, 18.0), respectively.

These data suggest that some physical disorders may be associated with increased suicidal ideation in primary care and may also play a role in the relationship between depression and suicidal ideation among primary care patients. Primary care physicians may wish to engage in an in-depth evaluation of psychiatric problems, especially current suicidal ideation, among patients with specific ongoing physical illnesses.