Serious Mental Illness
Also written as: SMI — Serious Mental Illness
A diagnostic and functional category designating mental disorders that substantially interfere with major life activities and persist over time, used in community psychiatry to determine service eligibility.
Full Definition
Serious mental illness (SMI) is defined by SAMHSA as a mental, behavioral, or emotional disorder resulting in serious functional impairment that substantially interferes with or limits one or more major life activities. The SMI designation typically encompasses schizophrenia spectrum disorders, bipolar disorder with psychotic features, and treatment-resistant major depressive disorder, among others. In editing eligibility criteria, policy documents, and grant applications, SMI must be distinguished from serious emotional disturbance (SED), which applies to children and adolescents. Editors should also note that 'severe mental illness' appears in British literature as a near-synonym, but the two terms have different regulatory histories in U.S. contexts. Capitalisation practice varies: some style guides mandate 'Serious Mental Illness' as a proper designation; house style should be applied consistently.
Usage
Usage note: In U.S. policy documents, prefer 'serious mental illness' over 'severe mental illness' unless the source explicitly uses the latter. Abbreviate to SMI only after first full use.
In Context
- "The programme serves adults aged 18 and older who meet the state definition of serious mental illness." — Service eligibility criteria
- "Prevalence data indicate that approximately 5.5% of U.S. adults live with serious mental illness in any given year." — Epidemiological report