Although the dose should be corrected according to the individual patient, often it is determined by habit rather than rational assessment (Br J Psych, 1992; 160: 621-37). Individual patients have individual seizure thresholds that is they require different amounts of electrical current to produce a seizure. This figure can vary by as much as 40 fold (Arch Gen Psych, 1987; 44:355-60; Psych Clin North Am, 1991; 14:803-43). The seizure threshold is higher for men than it is for women and rises with age. The aim of ECT should be to use the minimum amount of current necessary, within an optimal seizure length of between 20 to 50 seconds, to produce the seizure. Anything more can produce brain damage (N Eng J Med, 1993; 328:839-46). Psychotropic drugs can raise seizure thresholds. So can some of the anesthetics used during the procedure. This may cause physicians to give a bigger "fixed" dose, sometimes as much as 2.5 times greater than the seizure threshold, on a just in case basis, resulting in brain damage (Am J Psych, 1986;143:596-601). Higher doses are also routinely used because doctors believe they produce fast "results" (N Eng J Med, 1993; 328:839-46).
A dose below an individual's seizure threshold can increase the risk of cardiovascular complaints (Convulsive Ther, 1989; 5:35-43; Anaesth Intensive Care, 1988. 16:369-71; Am J Psych, 1984; 141:298-300)Surveys in the UK have shown that among doctors below consultant level there is no consistent method of training in ECT. Some did not recall ever being taught to administer ECT. Many did not have copies of relevant guidelines, and consultant supervision was rare (Psych Bulletin, 1993; 7(3):154-5; Br J Psych, 1992; 160:621-37).