Benzodiazepines and ECT Efficacy
Yes, benzodiazepines reduce ECT efficacy, particularly for right unilateral ECT, and should be discontinued prior to treatment when clinically feasible. 1, 2
Evidence for Reduced Efficacy
The impact of benzodiazepines on ECT outcomes depends critically on the type of ECT electrode placement used:
Unilateral ECT
- One prospective RCT and three large retrospective studies demonstrate that benzodiazepines significantly compromise the efficacy of unilateral ECT 2
- A case report documented minimal symptomatic improvement with right unilateral ultrabrief ECT while a patient was taking flurazepam and pregabalin, but achieved remission after discontinuation of these medications 2
- This electrode-specific effect is clinically significant because right unilateral ECT is increasingly preferred due to fewer cognitive side effects 3
Bilateral ECT
- The same studies found no association between benzodiazepine use and reduced efficacy for bilateral ECT 2
- One retrospective study of 90 patients receiving bitemporal ECT found benzodiazepine dose was not associated with changes in Hamilton Depression Rating Scale scores 4
- Paradoxically, one 2019 study reported higher remission rates (81.2% vs 52.0%) in patients receiving concomitant benzodiazepines with bilateral ECT using dose-titration method, though this contradicts the broader literature 5
Mechanism of Interference
Seizure Parameters
- Benzodiazepines consistently decrease seizure duration across multiple studies 2
- Most evidence shows no association with increased seizure threshold, contrary to what would be expected pharmacologically 2
- The clinical impact appears less pronounced than predicted by their anticonvulsant properties alone 2
Clinical Recommendations
Medication Management Strategy
- The American College of Psychiatry recommends discontinuing benzodiazepines, lithium, and carbamazepine prior to ECT due to risks of adverse effects 1
- This recommendation takes precedence even though some individual studies show conflicting results 4, 5
When Discontinuation May Not Be Feasible
- If benzodiazepines cannot be safely discontinued (e.g., severe alcohol or benzodiazepine withdrawal), bilateral electrode placement should be strongly preferred over unilateral 2
- The ESMO guidelines note benzodiazepines are the treatment of choice for alcohol or benzodiazepine withdrawal delirium, which may necessitate continuation during ECT in select cases 6
Important Caveats
Dosing Method Considerations
- Studies showing no effect used half-age dosing or dose-titration methods, which may not generalize to fixed high-dose protocols 4, 5
- Higher benzodiazepine doses may have greater negative impact, though this remains understudied 2
Population-Specific Effects
- Results may not generalize to populations less responsive to ECT or those with different underlying diagnoses 4
- The interaction between treatment resistance and benzodiazepine use remains incompletely characterized 7