Comparison of electroconvulsive therapy (ECT) with or without anti-epileptic drugs in bipolar disorder

Guidelines regarding the combination of anti-epileptic drugs (AEDs) and ECT have been contradictory. Evidence based knowledge about the advantages and disadvantages of this combination is sparse.

We studied the records of consecutive non-epileptic bipolar disorder patients referred for ECT between the months of January 2006 and January 2008 in an academic psychiatric hospital. Seizure threshold, failure to achieve adequate seizures, maximum electrical charge received and the number of ECTs administered were compared between those who were on AEDs during ECT (AED patients; n=79) and those who were not on AEDs (NAED patients; n=122). Two raters who achieved good inter-rater reliability assessed the clinical outcome from the records using the Clinical Global Impression (CGI) scale.

AED patients had significantly greater proportion of males, longer duration of episode and treatment and higher co morbidity. AED patients had significantly higher seizure threshold, higher incidence of failure to obtain seizures and shorter duration of motor seizures. Both groups achieved comparable symptomatic improvement at the end of the ECT course [Mean (SD) CGI-I=2.0 (0.4) and 1.96 (0.3) in AED and NAED patients respectively; t=1.4; p=0.15]. However, AED patients had received significantly higher number of ECT sessions [mean (SD)=7.9 (3.0)] than NAED patients [mean (SD)=6.3 (2.1); t=4.3; p<0.01] and stayed for significantly longer time (days) in the hospital [Mean (SD) 25.1 (16.1) and 20.6 (10.5) in AED and NAED patients respectively; t=2.4; p=0.02]. The difference in the outcome remained significant even after controlling for the effects of duration of illness, gender, drug treatment and presence of co morbidity.

Symptomatic improvement of patients who are on AEDS during ECT is comparable to those who are not. However, AED patients required a significantly higher number of ECT sessions to achieve this. Prospective studies are required to confirm these findings and also to compare cognitive adverse effects.