For centuries, it had been noted that psychosis did not tend to occur in those people with epilepsy. Since the 16th century, patients with severe mental illness were treated with various agents, such as camphor, to induce seizures (pharmacoconvulsive therapy). ECT was first instituted in the late 1930s and gained acceptance in providing a better controlled seizure. The addition of curare followed in 1951 by succinylcholine greatly diminished incidence of fracture due to the convulsions. Finally, the advent of methohexital, which ensured unconsciousness without significantly diminishing the seizure, led to the acceptance of ECT as an efficacious and safe treatment.

From the mid-1970s through the 1980s, many new drug treatments for psychiatric illness were developed and found to be efficacious. ECT fell into disfavor as a barbaric treatment when compared to pharmacotherapy.

In the past three decades, the pendulum has again swung back in favor of ECT as a safe and effective treatment for drug-resistant major depressive disorder and bipolar disorder.

Specific indications for ECT include, but are not limited to, major depressive disorder and bipolar disorder, acute schizophrenia (especially with affective or catatonic symptoms), and schizoaffective disorder. Although usually reserved as a second-line therapy for those who are resistant to pharmacologic treatment, ECT has, in some circumstances, been recommended as a first-line therapy, especially if a rapid response is urgently required as in patients with severe suicidal potential, malnutrition/dehydration, and catatonia. Finally, ECT has been recommended in patients who are unable to tolerate pharmacotherapeutic agents for any reason, including during pregnancy.

There is no absolute contraindication to ECT. There is considered to be significantly increased risk in patients with intracranial space occupying lesions, any condition associated with intracranial hypertension, recent myocardial infarction with diminished ventricular function, severe hypertension especially associated with pheochromocytoma, evolving stroke, retinal detachment, and any American Society of Anesthesiologists physical status 4 or 5 patient.

The mechanism of ECT is unknown. There are many neurochemical, neuroendocrine, electrophysiologic, and neuropsychological theories regarding the mechanism of ECT (see Table 60.1).

In addition, although it was long assumed that a generalized seizure of adequate duration is sufficient for effective treatment, research has shown that barely suprathreshold stimulation, especially with unilateral ECT is also efficacious. The cognitive impairment associated with ECT may be reduced by utilizing “ultrabrief” stimulus, marked by a shorter pulse width of electrical stimulation, apparently without sacrificing efficacy.

The cardiac status of the patient needs to be assessed as it would for any other general anesthetic. As there can be periods of significant tachycardia and hypertension following seizure induction, it would be useful to ensure that there is no longer significant myocardium at
risk for ischemia and that systolic function is not compromised. If this information cannot be obtained from patient history and assessment of his functional status, it may be useful to obtain a stress test and echocardiogram. Bear in mind that it may be difficult to get an accurate history of functional status from patients who are psychotic or severely depressed.

The anticoagulation for his atrial fibrillation should be continued throughout his course of therapy, maintaining an international normalized ratio (INR) between 2.0 and 3.0. Although intracerebral hemorrhage is a theoretic concern, a retrospective study from the Mayo Clinic suggests that ECT can be safely performed in patients on warfarin therapy. Although the safety of newer anticoagulants has not been formally investigated in ECT, case series do not report any hemorrhagic complication in patients receiving either dabigatran or rivaroxaban. Finally, if a patient has drug-eluting arterial stents, aspirin and clopidogrel or any alternative antiplatelet maintenance medication should be continued.