Beyond psychiatric diagnosis: detection-gap perspective on suicide decedents in a population-based cohort

BACKGROUND: A considerable proportion of individuals who die by suicide have no recorded psychiatric diagnosis, yet their psychosocial and clinical profiles remain poorly understood. AIMS: To examine whether conventional demographic, physical health, psychosocial and mental health characteristics distinguish suicide decedents with, versus without, psychiatric diagnoses in a population-based cohort. METHOD: This retrospective case-control study used UK Biobank baseline data linked with national mortality records. Suicide decedents were classified as having a recorded psychiatric diagnosis prior to death (PtD) or no recorded diagnosis (NPD). Group comparisons and logistic regression analyses examined associations between psychosocial variables and diagnostic status, including domain-specific multivariable models adjusted for age and gender. RESULTS: Among suicide decedents, 44% had no recorded psychiatric diagnosis. There were no significant differences between groups in smoking-related variables, diabetes, hyperlipidaemia, body mass index, social support or social connectedness. Hypertension, as well as the use of immunosuppressants and anti-inflammatory agents, were more prevalent in the PtD group. PtD individuals exhibited higher levels of anxiety-related traits, neuroticism and healthcare utilisation. In multivariable analyses, several unadjusted comparisons were attenuated. Neuroticism, 'suffering from nerves', healthcare utilisation and lower risk-taking remained significantly associated with PtD status whereas mood-related variables, including depressed mood and anhedonia, were no longer statistically significant following adjustment. CONCLUSIONS: Nearly half of suicide decedents had no recorded psychiatric diagnosis, and conventional psychosocial markers demonstrated limited discriminative value under current measurement conditions. These findings support a detection-gap framework and highlight the need for suicide prevention strategies extending beyond diagnosis-based approaches towards broader, population-level detection.