Obesity and autonomic dysfunction in schizophrenia: Associations with symptom severity and onset subtypes

Schizophrenia (SCZ) is associated with elevated cardiometabolic risk, including obesity and autonomic dysfunction. Reduced heart rate variability (HRV), reflecting impaired autonomic nervous system (ANS) function, is linked to increased mortality.

Seventy inpatients with SCZ were evaluated using the Positive and Negative Syndrome Scale (PANSS). HRV was measured via a standardized 5-min protocol evaluating ANS balance, vagal activity (VAG), and standard deviation of normal-to-normal intervals (SDNN). HRV data from 112 age-matched healthy controls were included for comparison.

SCZ patients exhibited significantly reduced SDNN compared to controls (17.8 ms vs. 40.5 ms, p < 0.001). Older individuals with obesity exhibited higher HRV than younger, non-obese patients (SDNN: 27.8 ms vs. 14.3 ms, p = 0.019). Early-onset SCZ patients with BMI <24 showed higher PANSS-N (28.3 vs. 22.1, p = 0.012) and PANSS-G scores (41.0 vs. 35.9, p = 0.049) without HRV differences. Conversely, late-onset cases, especially among non-obese patients, was associated with better ANS and VAG indices (ANS: PCC = 0.643, p = 0.01; VAG, PCC = 0.581, p = 0.023). Males had higher white blood cell counts, while females with BMI <24 showed higher PANSS-N scores (p < 0.05). Use of long-acting injectable antipsychotics was linked to higher PANSS-S in non-obese patients (7.4 vs. 4.1, p = 0.036).

Autonomic dysfunction is evident in SCZ, particularly in younger, non-obese individuals, and correlates with symptom severity and onset patterns. HRV and ANS metrics may serve as physiomarkers for risk stratification and personalized care.