Formula method for stimulus setting in bilateral electroconvulsive therapy: Relevance of age

Seizure thresholds were determined by titration in consecutive electroconvu lsive therapy (ECT) patients at the first (n = 146) and sixth (N = 83) ECT sessions. Equations to predict the threshold at the first and sixth ECT wer e computed from these data using a stepwise linear regression model. These equations were tested prospectively at the first ECT (n = 48) and sixth ECT (n = 26) sessions. Stimulus dose derived from the corresponding equations yielded adequate seizure (successful) in 82% and 84% of patients, respectiv ely. Predictions based on age alone (disregarding two other significant var iables-illness severity and inion-nasion distance) were estimated at these two ECT sessions. This would not appreciably compromise the success rate. T he "formula" method using age alone may therefore be used in routine clinic al practice.