Screening for Serious Mental Illness in the General Population

TLDR

Public Law 102‑321 created a block grant for adults with serious mental illness and tasked SAMHSA with estimating its prevalence. The authors developed and tested three screening instruments—CIDI‑SF, K10/K6, and WHO‑DAS—on 155 respondents, followed by DSM‑IV structured interviews and GAF scoring, defining SMI as any DSM‑IV disorder (excluding substance use) with a GAF below 60. All three scales correlated with SMI, but K10 and K6 performed best (AUC 0.854–0.865), with K6 achieving 0.36 sensitivity and 0.96 specificity, making it a brief, accurate screen for inclusion in clinical studies.

Abstract

<h3>Background</h3> Public Law 102-321 established a block grant for adults with "serious mental illness" (SMI) and required the Substance Abuse and Mental Health Services Administration (SAMHSA) to develop a method to estimate the prevalence of SMI. <h3>Methods</h3> Three SMI screening scales were developed for possible use in the SAMHSA National Household Survey on Drug Abuse: the Composite International Diagnostic Interview Short-Form (CIDI-SF) scale, the K10/K6 nonspecific distress scales, and the World Health Organization Disability Assessment Schedule (WHO-DAS). An enriched convenience sample of 155 respondents was administered all screening scales followed by the 12-month Structured Clinical Interview for<i>DSM-IV</i>and the Global Assessment of Functioning (GAF). We defined SMI as any 12-month<i>DSM-IV</i>disorder, other than a substance use disorder, with a GAF score of less than 60. <h3>Results</h3> All screening scales were significantly related to SMI. However, neither the CIDI-SF nor the WHO-DAS improved prediction significantly over the K10 or K6 scales. The area under the receiver operating characteristic curve of SMI was 0.854 for K10 and 0.865 for K6. The most efficient screening scale, K6, had a sensitivity (SE) of 0.36 (0.08) and a specificity of 0.96 (0.02) in predicting SMI. <h3>Conclusions</h3> The brevity and accuracy of the K6 and K10 scales make them attractive screens for SMI. Routine inclusion of either scale in clinical studies would create an important, and heretofore missing, crosswalk between community and clinical epidemiology.