Psychotic symptom burden and serum uric acid as correlates in a limited-adjustment analysis of current suicidal ideation in schizophrenia: a cross-sectional study

Abstract

Suicidal ideation is common in schizophrenia, but simple approaches combining symptom severity with routine biochemical measures remain limited. Serum uric acid, the end product of purine metabolism, is a routinely available peripheral measure linked to antioxidant activity, oxidative-inflammatory processes, and metabolic pathways, providing a rationale for its exploratory evaluation alongside psychotic symptom burden. We examined limited-adjustment associations of psychotic symptom burden and serum uric acid with current suicidal ideation in patients with schizophrenia and exploratorily evaluated the apparent discrimination of a combined model. This cross-sectional study included 134 patients with schizophrenia treated at Shanghai Jing’an District Mental Health Center from May 2021 to October 2023. Current suicidal ideation was defined as any nonzero response on item 4 or 5 of the Chinese Beck Scale for Suicide Ideation/Beck Scale for Suicide Ideation-Chinese Version (BSS/BSI-CV) during the preceding week. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Fasting blood samples were used to measure routine biochemical indicators. Between-group comparisons, prespecified limited-adjustment logistic regression, and auxiliary ROC analyses were performed. Data on body mass index, renal function, detailed medication exposure, urate-related treatment, and diet were unavailable. Current suicidal ideation was identified in 23 patients (17.2%). Patients with suicidal ideation had higher PANSS total, positive, and general psychopathology scores and higher serum uric acid levels. In the model adjusted only for age and sex, PANSS total score (odds ratio [OR] per 10-point increase = 2.05, 95% confidence interval [CI]: 1.27–3.31; p  = 0.003) and serum uric acid (OR per 100-µmol/L increase = 2.46, 95% CI: 1.16–5.25, p  = 0.019) remained associated with current suicidal ideation. Among the three ROC analyses, the combined model yielded the highest AUC (0.768, 95% CI: 0.657–0.865). Greater psychotic symptom burden and higher serum uric acid were associated with current suicidal ideation in schizophrenia. Serum uric acid should be interpreted as an exploratory biochemical correlate, not a mechanistic risk factor or validated biomarker. The model cannot be used for clinical prediction without further validation.