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.
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.
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.
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.