Effects of Repeated Electroconvulsive Therapy Sessions on Anesthetic Requirements

Electroconvulsive therapy (ECT) is an effective treatment for severe depression and other psychiatric disorders. ECT is usually given in several sessions on different days. During each session, patients receive short-acting anesthesia to ensure comfort and safety. This study aims to evaluate whether the amount of anesthetic medication required changes during repeated ECT sessions in the same patient. In addition, the study will examine the relationship between anesthetic dose, seizure duration, seizure quality (measured by postictal suppression index), and recovery time. This is a prospective observational study. All anesthesia and ECT procedures will be performed according to routine clinical practice. No additional intervention will be applied for research purposes.

Inclusion Criteria: * Age 18 to 65 years. * Scheduled to undergo electroconvulsive therapy (ECT) under elective conditions as part of routine clinical care. * ECT indication (e.g., major depressive disorder, bipolar depression, schizoaffective disorder, catatonia). * ASA Physical Status I-III. * Planned to receive multiple ECT sessions. * Able to provide written informed consent (participant and/or legally authorized representative). Exclusion Criteria: * Use of antiepileptic drugs or benzodiazepines that may affect seizure threshold. * ECT received within the past 6 months. * Severe cardiovascular, pulmonary, or neurologic comorbidity (investigator judgment). * Pregnancy or breastfeeding. * ASA Physical Status IV or higher. * Acute substance or alcohol use disorder/intoxication. * Conditions preventing EEG monitoring (e.g., scalp trauma, significant skin lesions, cranial implants). * Inability to obtain reliable BIS monitoring during anesthesia induction due to technical limitations.