ECT is administered by a specialized team of psychiatrists, anesthesiologists, and nurses. Prior to commencing the course of therapy, this team conducts a thorough general medical and neuropsychiatric examination of the patient in order to confirm the indications for ECT, to optimize the safety of the treatment by identifying and treating any general medical illnesses, to optimize the efficacy of the treatment by reviewing and potentially modifying the patient’s list of medications, and to commence the informed consent process. Although some illnesses may increase the risks of ECT, there are no absolute contraindications to the procedure.
ECT is typically administered in a special treatment suite. The patient should have nothing to eat or drink for at least 8 hours prior to the procedure. Once baseline vital signs, pulse oximetry, and an electrocardiogram (ECG) have been obtained, the patient is administered a short-acting anesthetic agent (typically methohexital) followed by a short-acting neuromuscular blocking agent (typically succinylcholine). Throughout the procedure, the patient is ventilated with 100% oxygen by mask, and vital signs are continuously monitored. Once the patient is asleep and fully paralyzed, a specially designed bite block is inserted into the patient’s mouth, and a brief electrical stimulus is then delivered across electrodes placed on the patient’s properly prepared scalp. The electrical stimulus dosage and the location of the treating electrodes (right unilateral, bitemporal, bifrontal) are both important to the efficacy and side effects of the procedure. The electrical stimulus elicits a generalized seizure that typically lasts 25 to 90 seconds and is monitored continuously with electroencephalography (EEG). During the initial tonic motor phase of the convulsion, EEG activity is variable, consisting of low-voltage fast activity with polyspike rhythms. EEG activity rapidly evolves into the hypersynchronous polyspikes and waves that characterize the clonic motor phase. These regular patterns begin to slow and eventually disintegrate as the seizure ends, usually terminating abruptly in a “flat” EEG. Ventilatory support is maintained until the patient emerges from the anesthesia, and further recovery is provided in an environment with as little stimulation as possible. The entire procedure takes about 20 minutes, and patients are often able to have a snack within an hour of the procedure, after which they are discharged.
When used to treat acute illnesses, ECT is typically administered three times a week, on a Monday, Wednesday, Friday schedule, until a therapeutic benefit has been maximized (typically six to 12 treatments). Most patients receive the treatment on an outpatient basis, depending on their clinical status and the availability of appropriate logistical support. Response rates range from 65% to 90%, depending on a number of factors. After a successful acute course ECT, ECT may also be employed as continuation or maintenance therapy, the goal of which is to prevent recurrence. During a continuation or maintenance course of therapy, ECT is administered at decreasing frequencies (tapering from weekly to monthly or longer) and continued for at least 12 months.
The primary diagnostic indications for which ECT is safe and effective include each of the major mood episodes (ie, major depressive, manic, mixed), schizophrenia and schizoaffective disorder, and catatonia (especially malignant variants, such as neuroleptic malignant syndrome). Despite having the broadest spectrum of therapeutic activity of any modern biological treatment in neuropsychiatry, ECT is used mainly to treat patients suffering from depression (15). ECT is indicated anytime a patient is gravely ill and in need of a rapid, definitive response (eg, acutely suicidal, melancholic with severe inanition) and is typically used when other treatments (typically medications) have failed or are poorly tolerated, when the patient has a history of a good response to ECT, or when the patient prefers ECT (02).
Secondary indications for ECT include mood disorders due to general medical or neurologic conditions (eg, secondary mood disorders) as well as certain neurologic conditions themselves (see Special considerations).
There are no absolute contraindications to ECT. It is safe and effective in children and adolescents, women who are pregnant, and the elderly. In persons with certain general medical conditions, ECT may be safer than pharmacotherapy.
ECT results in a marked activation of the autonomic nervous system, and the relative balance of parasympathetic and sympathetic nervous system activity determines the observed cardiovascular effects. These effects combine to produce a brief increase in cardiac workload and occasional transient arrhythmias, which are well tolerated by most patients. Patients with significant cardiac disease may require modifications in ECT technique to optimize the cardiovascular safety of the procedure.
The ECT seizure is also associated with a variety of transient and benign changes in cerebral physiology, including cerebral blood flow, cerebral blood volume, and cerebral metabolism. The brief increase in intracranial pressure is rarely of clinical consequence, but it is the reason for the well-known proscription against ECT in patients with a space-occupying intracranial mass. Transient disruption of blood-brain barrier permeability likely occurs during the seizure and may account for a transient increase in T1 relaxation times on brain magnetic resonance imaging (MRI).
ECT is the single most effective, as well as the most rapidly effective, treatment for major depression (12). Randomized, controlled data from the Consortium for Research in ECT (CORE) indicate that remission occurs in 70% to 90% of patients who receive ECT (09). Remission rates are even higher among patients with psychotic depression and among the elderly (21; 25). This success compares to remission rates of approximately 30% for pharmacotherapy and repetitive transcranial magnetic stimulation (28; 24). ECT’s efficacy does not depend on whether the depression is unipolar or bipolar. However, ECT using ultrabrief pulse width appears less efficacious than standard brief pulse ECT (32). For individuals with medication-resistant depression, ECT is a cost-effective treatment option (27). ECT is similarly safe and effective among children and adolescents (23).
Some patients report immediate improvement after a single ECT treatment, and approximately 60% of patients with major depression achieve full remission after nine treatments (09). Despite its robust results, ECT is not curative. Symptom recurrence occurs in a majority of patients if ECT is discontinued (10). Randomized, controlled data indicate that maintenance therapy with ECT (utilizing the same technique as was effective during the acute course) and pharmacotherapy (lithium plus nortriptyline) are comparable, with both forms of therapy sustaining remission rates for about half of patients after 6 months (14). Randomized, controlled data also indicate that, among elderly persons, the combination of continuation ECT plus venlafaxine is superior to venlafaxine alone at 24 weeks after the completion of an acute course of ECT (13). Many patients with chronically recurring forms of severe illness receive lifelong maintenance ECT.
For patients suffering from mania, ECT remits symptoms approximately 80% of the time (17). The treatment can be lifesaving for patients suffering from manic delirium.
Remission rates are comparable in schizophrenia. Although a higher number of treatments (eg, 12 to 15) may be required, cognitive side effects are typically transient and mild (29). The combination of ECT with clozapine appears to be more effective than ECT alone (22).
The safety of ECT compares favorably with that of any treatment requiring general anesthesia. ECT mortality in adults is reported as approximately less than one death per 10,000 patients (roughly one per 80,000 treatments), which is about the same as mortality from general anesthesia for minor surgery (02). Such systemic side effects as headache, nausea, and myalgia are common during and shortly after the post-ECT recovery period. These symptoms are generally mild, transient, and quite responsive to symptomatic treatment (04).
Cognitive side effects are common after ECT and include a brief period of confusion and, rarely, frank delirium immediately on awakening from anesthesia. ECT is also associated with transient impairments in retrograde and anterograde memory, and roughly half of patients will subjectively report some degree of memory trouble (26). Autobiographical memory is less affected (16). The frequency and severity of these amnesic side effects vary with a number of patient factors (eg, age, preexisting cognitive impairment, general medical health) and ECT technical factors (eg, stimulus electrode placement, stimulus waveform). In general, the amnesic effects of ECT are short-lived (days to weeks in duration), do not cause major functional impairment, and must be distinguished from the amnesic effects of illness (eg, depressive pseudodementia) (02; 30). There is no evidence that ECT causes structural brain damage. Patient education on this topic is important as patients with negative expectations of the amnestic side effects of ECT are more likely to experience subjective worsening of memory following ECT (31). Misinformation and misunderstanding of these cognitive side effects remain the primary source of stigma and controversy that limit access to ECT (20).
Mood disorders are common in patients with neurologic illness, and many of those patients will require treatment with ECT. Although there are no controlled data on the efficacy of ECT in these conditions, extensive clinical experience and a primarily retrospective literature support such use. The administration of ECT in such patients may require modifications in the technique of the procedure in order to optimize safety and efficacy. The neurologist can play an important role in ensuring the appropriate and safe use of ECT in these individuals. ECT should be considered in depressed patients with Alzheimer disease, Parkinson disease, Huntington disease, stroke, epilepsy, multiple sclerosis, traumatic brain injury, and brain tumor.
In addition, the neurobiological effects of ECT may have beneficial effects on a number of neuropsychiatric disorders, most notably those discussed here.
Dementia. Growing evidence suggests that ECT may be helpful for treating symptoms of agitation and aggression in patients with dementia. In such settings, ECT appears to be safe, well-tolerated, associated with a reduction in the PRN (as required) use of sedating medications, and, in some cases, rapidly effective (01; 08).
Autism. Self-injurious behaviors and other signs of catatonia are an increasingly important indication for ECT. Although the feasibility of controlled trials in this population is limited, accumulating case series data, particularly in children and adolescents, support the safety and efficacy—sometimes life-saving—of ECT and suggest it should be considered promptly (19).
Anti-NMDA receptor encephalitis. Accumulating case report data suggest that ECT may be helpful in treating the neuropsychiatric symptoms of anti-NMDA receptor encephalitis, particularly catatonia (05). ECT may have a disease-modifying effect on this form of autoimmune encephalitis.
Neuroleptic malignant syndrome (NMS). ECT has been used to successfully treat severe, refractory cases of NMS (33). Such patients should be off all dopamine-blocking drugs, however, and a non-depolarizing muscle relaxant (rather than succinylcholine) may be indicated in patients with prolonged immobility.
Parkinson disease. ECT may be a useful treatment for the motor disturbances of severe Parkinson disease when pharmacotherapy is unsuccessful or not tolerated, irrespective of the procedure’s effect on the patient’s mood. These data include a randomized controlled trial with sham ECT of 11 patients with the “on-off” syndrome (03). This salutary effect is not surprising given that ECT has been shown to enhance dopaminergic function (12). The beneficial effects of ECT on motor function may be maintained for months with maintenance ECT treatments.
Intractable seizures. Animal studies demonstrate that electroconvulsive seizures have anticonvulsant properties in that they block kindling and raise seizure threshold. This anticonvulsant effect whereby seizure threshold rises and seizure duration shortens during a course of ECT is also seen in humans (11). There are clinical reports of clinicians who have leveraged this anticonvulsant property of ECT to terminate status epilepticus in some patients, or decrease the frequency of seizures in others (07). It has been suggested that a course of ECT might be considered in some patients with intractable epilepsy prior to undergoing brain surgery.
Delirium. ECT has been administered safely and effectively in patients with delirium associated with a broad range of etiologies (18). ECT may be effective for delirium even when the underlying etiology has not been identified or corrected, and patients with delirium do not appear to be at any greater risk of cognitive side effects from ECT. On the basis of this large clinical experience, ECT is routinely used for the management of delirium in Scandinavia; ECT is probably underutilized as a treatment for delirium in the United States.
A 75-year-old married man with Parkinson disease developed a major depressive episode characterized by an overwhelmingly apprehensive mood that did not react to positive or pleasurable circumstances. The mood disturbance lasted for 6 months and was accompanied by anorexia with weight loss, insomnia, loss of pleasure, impaired concentration, guilty ruminations, somatic delusions of having a terminal illness, and thoughts of suicide via drug overdose. His psychiatrist prescribed an antidepressant medication that, although it had been effective in the past, provided little symptom relief and caused intolerable side effects. He was tapered off his antidepressant medication and commenced a course of bifrontal ECT. After receiving six ECT treatments on a Monday, Wednesday, Friday schedule, his depression symptoms were 50% improved, and he began experiencing confusion between treatments. The ECT schedule was modified to twice weekly treatments. After his ninth ECT treatment, his depression symptoms fully remitted, the confusion resolved, and he noticed modest improvement in his parkinsonism. He had difficulty recalling certain events that occurred during the course of ECT, but did not find this side effect distressing. Given his history of recurrent episodes of major depression, he elected to continue receiving ECT as part of a maintenance course of therapy. Once the schedule was tapered to one ECT treatment each month, his memory impairments resolved while the improvement in his motor symptoms was maintained. During the next several months of his maintenance course of ECT, his depressive illness remained fully remitted, and he required no antidepressant medication.