Background: 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. Methods: 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. Results: 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). Conclusion: 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.
