Characteristics of Adults with Serious Psychological Distress As Measured by the K6 Scale: United States, 2001-04

Objective: This report estimates the prevalence of serious psychological distress (SPD) in the noninstitutionalized adult population of the United States, as measured by the K6 scale of nonspecific psychological distress, and describes the characteristics of adults with and without SPD. These findings are compared with results from previous studies of the characteristics of adults with serious mental illnesses that cause significant disability, such as severe major depression, bipolar disorder, and schizophrenia.

Methods: The estimates in this report were derived from the Family Core and Sample Adult components of the 2001-04 National Health Interview Survey, conducted by the Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS). Estimates were calculated using the SUDAAN statistical package to account for the complex survey design.

Results: The prevalence of SPD was higher among adults 45-64 years old than younger adults 18-44 years or older adults 65 years and over. Adults with SPD were more likely to be female, have less than a high school diploma, and live in poverty, and less likely to be married than adults without SPD. Moreover, those with SPD were more likely to be obese and to be current smokers. They have a higher prevalence of ever being diagnosed with heart disease, diabetes, arthritis, and stroke than persons without SPD. Adults with SPD were more likely to report needing help with activities of daily living (ADLs) and instrumental activities of daily living (IADLs). They also used more medical care services such as doctor visits and visits to mental health professionals than adults without SPD.

Conclusions: The associations between SPD and sociodemographic characteristics, health status, and health care utilization are similar to the relationships found between serious mental illnesses (for example, major depression or schizophrenia) and these same variables. Persons with SPD demonstrate disadvantage in both socioeconomic status and health outcomes.