Increased stimulation intensity helped cope with protracted seizures


Modified electroconvulsive therapy (mECT) is a highly recommended treatment option for drug-resistant major depressive disorder.1 In general, the safety profile of mECT is relatively good; however, in rare cases, complications of prolonged seizures lasting longer than 180 sec may occur.2 Prolonged seizures during mECT are reported at 1–2%.3 There are many protocols to counter protracted seizures during mECT, such as anesthetic adjustments and ventilation.4 The evidence on methods for deciding whether or not to continue the next cycle of mECT after a prolonged attack and for preventing recurrent attacks is currently not well established. However, the clinician’s choice to discontinue mECT due to the onset of protracted seizures may lead to difficulties in treating the patient’s primary disease and compromise therapeutic benefits. A previous report showed that right unilateral electroconvulsive therapy could cope with protracted seizures by increasing stimulus intensity.5

This report showed that increased stimulation intensity helped cope with a prolonged seizure during the next round of mECT on both sides.

Case report

The patient was a 76-year-old woman. At the age of 70, when she was admitted to the collagen medicine department of our hospital with polymyositis, she first developed a depressive state and was subsequently treated by the psychiatry department. She was diagnosed with major depressive disorder by the Diagnostic and Statistical Manual of Mental Disorders IV-TR and treated with mirtazapine 45 mg; however, his depressive state and anxious restlessness did not improve. She subsequently failed to respond to various drug treatments, including escitalopram, venlafaxine, vortioxetine, and augmentation with aripiprazole, and underwent initial mECT at age 72. The depressive state improved immediately after mECT, but she relapsed several times, requiring mECT. every time.

At the age of 76, she was admitted to our hospital to undergo mECT for the fifth time due to recurring depressive symptoms such as decreased appetite, anxiety and restlessness. After admission, vortioxetine 10 mg and olanzapine 10 mg were tapered. Quetiapine 50 mg, suvorexant 15 mg, and trazodone 25 mg were continued. Propofol (1.0 mg/kg) was given intravenously and rocuronium bromide (1.0 mg/kg) was given to prevent muscle twitching. After induction of anesthesia, suxamethonium chloride (4.0–5.0 mg/kg) was administered intravenously as a muscle relaxant. The mECT was bilateral and started at 35% stimulation intensity, and effective seizures were achieved for the first time. However, during the 8th mECT at the same intensity (35% stimulus intensity), an unexpected prolonged seizure of 966 s (over 16 minutes) occurred. The attack was abruptly stopped with diazepam 10 mg and midazolam 2 mg. There were no late attacks. The patient had used a range of antidepressants in the past with poor efficacy, therefore we considered that continuation of ECTm might be reasonable to improve her depressive symptoms.

During the ninth session of mECT, stimulation intensity was increased to 50%, resulting in effective seizures and no prolonged seizures. Subsequently, appropriate convulsions were obtained with the same intensity of stimulation, and she performed 12 sessions. Her depressive symptoms improved both subjectively and objectively, and she was discharged on the 45th day of hospitalization.


This report has two main clinical indications. Prolonged seizures in mECT can be avoided by increasing stimulation intensity during the next cycle. This method was also effective in the next mECT after a prolonged convulsion lasting more than 16 minutes.

While in general the safety profile of mECT is relatively good, a few rare cases of complications from protracted seizures lasting longer than 180 s have been reported at 1–2%.2.3 A hypothesized mechanism for developing protracted seizures is that when the amount of stimulation approaches the epileptogenic threshold, the brain’s inhibitory mechanisms fail to recognize the seizure and terminate it.5 A higher than threshold stimulation dose would readily employ these inhibitory mechanisms.5 Some reports suggest that the duration of seizures appears to be inversely proportional to the amount of stimulation.6 Increasing the stimulus dose in the second mECT treatment after the first titration session results in a significantly shorter seizure This case report was consistent with the above hypothesis and showed that prolonged seizures lasting just over 16 minutes could be treated by increasing the intensity of the next stimulus. Seizure thresholds may increase along with mECT frequency.8 As the quality of mECT seizures was strongly correlated with the decrease in depressive symptoms,9 the method of increasing stimulus intensity was appropriate. To our knowledge, this is the first report in which prolonged seizures longer than 16 minutes could be suppressed by only increasing stimulus intensity on the next mECT.

Prolonged seizures can occur suddenly, although in patients who have already undergone several mECT sessions like ours, the occurrence of a prolonged seizure during mECT does not immediately preclude the use of mECT the next time. it is done. Nor is the length of the prolonged duration a direct cause for reluctance to use mECT again. The risks and benefits should be carefully weighed when deciding whether or not to provide mECT after protracted seizures. However, the present case implies that protracted seizures can be avoided by increasing the stimulation intensity during the following cycle. We could not generalize the case of major depressive disorder with mECT, accumulating such cases must be done.


In conclusion, the present case implies that prolonged seizures in mECT can be avoided by increasing stimulation intensity during the next cycle.

Data Sharing Statement

The datasets used and/or analyzed during this case report are available from the corresponding author upon reasonable request.

Ethics approval and consent to publication

All the actions described in this study were carried out in compliance with the rules of ethics. Informed consent was obtained from the patient for the publication of her anonymous information in this manuscript. This study was a case report and the University of Occupational Health and Environmental Ethics Committee excused the review.

Author’s contributions

All authors made significant contributions to the work reported, whether in conception, study design, execution, data acquisition, analysis and interpretation, or all of these areas; participated in writing, editing or critically reviewing the article; gave final approval to the version to be published; have agreed on the journal to which the article has been submitted; and agree to be responsible for all aspects of the job.


This study did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sectors.


The authors report no conflict of interest in this work.


1. UK ECT Examination Group. Effectiveness and safety of electroconvulsive therapy in depressive disorders: a systematic review and meta-analysis. Lancet. 2003;361(9360):799–808. DOI:10.1016/S0140-6736(03)12705-5

2. Cristancho MA, Alici Y, Augoustides JG, O’Reardon JP. Rare but serious complications associated with electroconvulsive therapy: recognition and management for the clinician. Curr Representative in Psychiatry. 2008;10(6):474–480. doi:10.1007/s11920-008-0076-4

3. Scott AI, McCreadie RG. Prolonged seizures detectable by electroencephalogram in electroconvulsive therapy. Br J Psychiatry. 1999;175:91–92. doi:10.1192/bjp.175.1.91b

4. Mankad MV, Beyer JL, Weiner RD, et al. Electroconvulsive therapy clinical manual. Washington District of Columbia: American Psychiatric Publishing; 2010.

5.Goh SE, TorPC. Selection of right unilateral placement to facilitate continuation of electroconvulsive therapy after prolonged seizures. Asian J Psychiatrist. 2021;66:102874. doi:10.1016/j.ajp.2021.102874

6. Frey R, Heiden A, Scharfetter J, et al. Inverse relationship between stimulus intensity and seizure duration: implications for the ECT procedure. J ECT. 2001;17(2):102–108. doi:10.1097/00124509-200106000-00004

7.Chung KF. Relationships between seizure duration and seizure threshold and stimulus dose in electroconvulsive therapy: implications for electroconvulsive therapy practice. Psychiatry Clin Neurosci. 2002;56(5):521–526. doi:10.1046/j.1440-1819.2002.01048.x

8. Coffey CE, Lucke J, Weiner RD, et al. Epileptogenic threshold in electroconvulsive therapy (ECT) II. The anticonvulsant effect of ECT. Biol Psychiatry. 1995;37(11):777–788. doi:10.1016/0006-3223(95)00053-J

9. Minelli A, Abate M, Zampieri E, et al. Markers of seizure adequacy and prediction of response to electroconvulsive therapy. J ECT. 2016;32(2):88–92. doi:10.1097/YCT.0000000000000274

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