ObjectiveThis study examined the incidence of metabolic syndrome (MetS) in individuals with bipolar disorder (BD) and identified clinical and biological predictors of incident MetS during a 1-year follow-up.MethodsThe study included 100 euthymic BD type-1 patients consecutively recruited from outpatient clinics between July 2023 and July 2024. MetS was defined according to International Diabetes Federation criteria. Patients without MetS at baseline but with MetS during follow-up were classified as having incident MetS. A logistic regression model was utilized to estimate the adjusted odds ratios (OR) and corresponding 95% confidence intervals (CIs) for associations between predictors and incident MetS.ResultsOf the participants enrolled in the study (n = 100, 92% response rate), 29% met MetS criteria at baseline. Of the 71 without baseline MetS, 29 (40.8%) developed MetS over a 1-year period. Significant predictors of MetS onset included a higher number of manic/hypomanic episodes (OR = 1.459, 95% CI = 1.005-2.118, P = .047), increased chlorpromazine-equivalent antipsychotic dosages (OR = 1.007, 95% CI = 1.001-1.013, P = .024), high waist circumference (OR = 1.247, 95% CI = 1.052-1.479, P = .011), and hypertriglyceridemia (OR = 1.041, 95% CI = 1.007-1.077, P = .020). Conversely, lamotrigine use was inversely associated with MetS development (OR = 0.030, 95% CI = 0.001-0.659, P = .026).ConclusionA high incidence of MetS (41%) was observed during a 1-year follow-up of patients with BD in Turkey. Identified risk factors highlight opportunities for intervention through mood recurrence prevention, careful pharmacotherapy management, and treatment of pre-existing components of MetS.