Outcomes of subsyndromal depression in older primary care patients

Most older persons in primary care suffering clinically significant depressive symptoms do not meet criteria for major or minor depression. The authors tested the hypothesis that patients with subsyndromal depression (SSD) would have poorer psychiatric, medical, and functional outcomes at follow-up than nondepressed patients but not as poor as those with minor or major depression. The authors also explored the relative outcomes of three definitions of SSD to determine their relative prognostic value.

Prospective observational cohort study.

Primary care practices in Monroe County, NY.

Four hundred eighty-one primary care patients aged 65 years and older who completed research assessments at intake and at least 1 year of follow-up evaluation.

Depression diagnoses and three definitions of SSD were determined by the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and the 24-item Hamilton Depression Rating Scale. Other validated measures assessed anxiety, cognition, medical burden, and functional status.

Patients with SSD had poorer 1-year lagged outcomes than nondepressed subjects in terms of psychiatric symptoms and functional status, often not significantly different than major or minor depression. Two of the SSD definitions identified subjects with poorer psychiatric and functional outcomes than the third SSD definition.

Clinicians should be vigilant in caring for patients with SSD, monitoring for persistent, or worsening depressive symptoms including suicidality, anxiety, cognitive impairment, and functional decline. Researchers may use particular SSD definitions to identify individuals at higher risk of poor outcomes, to better understand the relationships of SSD to functional disability, and to test innovative preventive and therapeutic interventions.