Subthreshold psychiatric symptoms in a primary care group practice.

Background: The authors define 6 groups of subthreshold psychiatric symptoms that do not meet the full criteria for a DSM-IV Axis I disorder and examine the clinical significance of these symptoms in an outpatient primary care sample.

Methods: The subjects were 1001 adult primary care patients in a large health maintenance organization. Data on sociodemographic characteristics and functional impairment, including scores on the Sheehan Disability Scale, were collected at the time of the medical visit, and a structured diagnostic interview for DSM-IV disorders was completed by telephone within 4 days of the visit. Subthreshold symptoms were defined for depressive, anxiety, panic, obsessive-compulsive, drug, and alcohol symptoms.

Results: Subthreshold symptoms were as or more common than their respective Axis I disorders: panic (10.5% vs 4.8%), depression (9.1% vs 7.3%), anxiety (6.6% vs 3.7%), obsessive-compulsive (5.8% vs 1.4%), and alcohol (5.3% vs 5.2%) and other drug (3.7% vs 2.4%) cases. Patients with each of the subthreshold symptoms had significantly higher Sheehan Disability Scale scores (greater impairment) than did patients with no psychiatric symptoms. Many patients (22.6%-53.4%) with subthreshold symptoms also met the full criteria for other Axis I disorders. After adjusting for the confounding effects of other Axis I disorders, other subthreshold symptoms, age, sex, race, marital status, and perceived physical health status, only depressive symptoms, major depressive disorder, and, to a lesser extent, panic symptoms were significantly correlated with the impairment measures.

Conclusions: In these primary care patients, the morbidity of subthreshold symptoms was often explained by confounding mental, physical, or demographic factors. However, depressive symptoms and, to a lesser extent, panic symptoms were disabling even after controlling for these factors. Primary care clinicians who detect subthreshold psychiatric symptoms should consider a broad psychiatric assessment.