Aim: In this naturalistic study the aim was to examine the impact on seizure duration of stimulus intensity, previous
treatments (during the first course of ECT), age, gender, and electrode placement.
Method: The database of the ECT Service of the Royal Hobart Hospital was examined for the 15 years ending in
2010. First courses of ECT were identified in which the stimulus intensity was not altered and at least 5 treatments
were provided. Seizure duration was determined by cessation of clonic movements.
Result: 383 patients (164 males) met selection criteria. A multiple regression analysis revealed that previous treatments,
age, gender, and electrode placement had non-significant regression coefficient on the seizure length. The stimulus
intensity, however, showed significant regression coefficient (-.267, p <.001), indicating that higher stimulus intensity
induced shorter seizure duration.
Conclusion: It was suggested that electrode placement and the number of treatments had negligible influence on seizure
duration, while high stimulus intensity reduced seizure duration. If fixed high dose ECT is being provided, and there
is concern due to the brevity of seizures, rather than taking steps to increase the output of the machine, a modest reduction
of dose (perhaps to < 428.4 mC, or < 85% of machine output) may increase seizure duration (German J Psychiatry
2011; 14: 35–39).