Effects of long-acting injectable antipsychotics versus oral antipsychotics on autonomic nervous system activity in schizophrenic patients

Objective: Long-acting injections (LAIs) of antipsychotics show distinct pharmacokinetic profiles from oral antipsychotics (OAPs). Although there may be differences in adverse event frequency, any differences in their effects on autonomic nervous system (ANS) remain unclear. Patients and methods: In total, 270 schizophrenic patients were recruited in this study: 241 received OAPs (risperidone, olanzapine, quetiapine, or aripiprazole) and 29 received LAIs (risperidone LAI, aripiprazole LAI, or paliperidone palmitate) as monotherapy. Heart rate variability was measured as an index of ANS activity, and the low-frequency (0.03–0.15 Hz) component, high-frequency (0.15–0.40 Hz) component, and total power (0.03–0.40 Hz) were calculated. Components were compared between the groups using t-tests. Results: A significant difference was detected in the low-frequency component between the OAP and LAI groups ( P =0.046). No significant difference was found in total power or the high-frequency component between the two groups. Conclusion: Compared with OAPs, LAIs have fewer adverse effects on ANS activity, particularly the low-frequency component, as determined using a spectral analysis of heart rate variability.