When is ECT indicated in psychiatric disorders?
Electroconvulsive therapy is still one of the most powerful psychiatric treatments available. Deciding when to use it for patients who are depressed, manic, or schizophrenic is a common challenge facing clinicians.
Although numerous psychotropic agents in multiple classes have emerged over the past few decades, electroconvulsive therapy (ECT) still represents an essential treatment in modern psychiatry. Its record of safety and efficacy is virtually unparalleled vis a vis pharmacological agents.
Advances in anesthetic technique, electrode placement, and electrical stimulus dosing allow ECT to be administered safely to even the most medically ill patients without excessive effects on memory, with excellent clinical benefits (Box 1). A typical course of ECT consists of 8 to 10 treatments administered 2 to 3 times per week.
The medical complications of ECT are rare, and good pre-treatment medical assessment helps ensure its safety. 1 Include at minimum a medical history, physical exam, and basic laboratory tests. Specialist consultations are sometimes necessary when patients have comorbid neurologic or cardiologic illnesses (Box 2).
The most bothersome side effect of ECT is memory disturbance. This takes 3 forms: post-treatment confusion and anterograde or retrograde amnesia (Box 3). Less serious side effects include headaches, muscle soreness, and nausea. These are easily treated symptomatically with analgesics or antiemetics.
THE TECHNICAL FACTORS OF ECT AFFECTING EFFICACY AND SIDE EFFECTS
Electroconvulsive therapy (ECT) has been in use since 1938. 6 It consists of the application of an electric current to the head, which causes a seizure.
Modern ECT technique involves the use of general anesthesia, usually with a barbiturate anesthetic such as methohexital, and muscular paralysis, usually with the depolarizing neuromuscular blocking agent succinylcholine. Continuous oxygenation with positive pressure ventilation, measuring of blood pressure, and monitoring with an electrocardiogram and pulse oximetry make the procedure exceedingly safe.
Efficacy and cognitive side effects may be affected by how ECT is administered. The two treatment electrodes that are placed on the head can be located on either side of the temporal fossa (the bitemporal position), on either side of the forehead (the bifrontal position), or on the right temporal fossa and just to the right of the vertex of the skull (the d’Elia unilateral position). Generally, unilateral electrode placement causes less memory impairment but has been believed to be less effective than bilateral electrode positions. 6
Another technical factor receiving attention from researchers is the amount of electricity, or electrical dose, used to elicit the seizure. Generally, especially for unilateral ECT, high electrical doses are needed to attain acceptable treatment efficacy. In fact, one study indicates that if 6 times the minimum electrical seizure threshold is used for unilateral ECT, efficacy for depression is equal to that of bilateral ECT with less memory disturbance. 23
Finally, treatment frequency affects ECT outcome: twice-weekly treatment schedules are associated with less memory disturbance—and only slightly slower clinical response—than thrice-weekly schedules. 24
The most common indication for ECT is major depression. Using modern diagnostic criteria, most depressed patients respond to ECT. Some features that presage a particularly robust response include psychomotor retardation, psychosis, catatonia, and advanced age. Patients who have medication-resistant depression may require particularly potent forms of treatment, such as bilateral electrode placement and/or higher than usual electrical doses.
Patients with mania respond particularly well to ECT but, because of excellent responses with modern pharmacological agents, rarely need it. For patients with mania who are agitated and noncompliant, ECT may represent a life-saving option for stabilizing an acute episode. Finally, ECT may help yield stability for an acute exacerbation of schizophrenia or may extend the benefits of antipsychotic medication for those with chronic schizophrenia, in which case continuation of ECT is usually advisable.
When ECT is indicated for depression
Typical depressed patients receiving ECT have experienced functional decline and have resisted, or have not tolerated, antidepressant medication. Several specific factors affect whether ECT will help particular depressed patients:
Melancholic features From the earliest use of ECT, it seemed apparent that patients with melancholic depression respond better to ECT than do patients with atypical or mood-reactive depression. Early research seems to have borne this out. Roberts 2 found that melancholic features such as psychomotor retardation and guilty ideations strongly and favorably predicted ECT response. More recent research, however, generally fails to find predictive value in ECT response in patients based on presence of melancholia. 3
WHEN MEDICAL ILLNESS REQUIRES A CONSULTATION BEFORE ECT
The medical and neurologic illnesses that place prospective ECT patients at higher than usual risk of complications include a brain tumor or other intracranial space-occupying lesion, increased intracranial pressure, unstable cardiac function, or high anesthetic risk. 25
Patients with severe cardiac disease, such as congestive heart failure, coronary artery disease, or cardiac dysrhythmia, can almost always be treated with ECT safely with adequate attention to pretreatment medical stabilization and use of antihypertensive medications during the treatment to blunt the increase in myocardial oxygen demand during the seizures.
Why is this? Several factors likely explain this rather dramatic difference. First, the patients given ECT in the early decades of its use most likely suffered with a diverse range of dysphoric states (e.g., patients with “neurotic” depression, dysthymia, or personality disorders), while modern research has been limited to relatively homogeneous samples of patients with major depression defined according to strict research criteria. 3 When you try to correlate a putative predictive variable such as presence vs. absence of melancholia with an outcome variable such as reduction in depression ratings, the less variability there is on the predictive variable, the less strong the correlation will be.
Another possible factor accounting for the lack of predictability is a broadened concept of melancholia. According to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), 4 it is possible to have melancholic depression without having weight loss, psychomotor retardation, or excessive guilt—3 signs classically thought to be inherent in the melancholic syndrome. If melancholia is defined more narrowly, to include requirements for weight loss and psychomotor change, then it is probably more likely to correlate with ECT response.
A final potential reason for lack of predictability is the method of ascertaining melancholia. In modern samples, usually the Hamilton Rating Scale for Depression is used. 5 Such a scale is administered in a brief interview by a research clinician not familiar with any other aspects of the patient’s mental status. In contrast, in some early studies, 2 melancholic signs were ascertained by complete psychiatric history and evaluations as done in clinical practice. Such methods are likely to yield more reliable data on weight loss, guilty ideations, psychomotor activity, and other signs than is a 15-to 20-minute interview conducted by a research technician.
Along these lines, Hickie et al, 6 utilizing a thorough evaluation of psychomotor activity before ECT, found that psychomotor retardation robustly predicted positive ECT response. Their scale utilized numerous items assessing agitation and retardation, and required a longer period of assessment than did the Hamilton scale; the latter scale has only 2 items for psychomotor activity, each one a global assessment of agitation or retardation.
So do you consider ECT for patients with melancholic features? Yes. Patients with classic melancholic features such as weight loss, pronounced guilt, and especially psychomotor retardation stand an excellent chance of substantial relief with a course of ECT. Additionally, patients with nonmelancholic depression have good response rates with ECT.
WHAT TO TELL YOUR ECT PATIENTS ABOUT MEMORY DISTURBANCE
Patients and their families are frequently concerned about the effects of ECT on memory. The 3 types of memory disturbances to discuss are:
- Post-treatment confusion and disorientation. This state usually lasts from a few minutes to several hours or, in the case of some elderly patients after receiving numerous treatments, several days. This state is always reversible.
- Anterograde amnesia. This is the inability to recall newly learned information during and up to a few weeks after the course of treatments. During this time, any information given to the ECT patient may not be remembered. Important strategies are to write down instructions and make sure that family members are informed of the need to repeat things and monitor the patient if an outpatient. Fortunately, antero-grade amnesia is also reversible.
- Retrograde amnesia. This refers to the forgetting of personal life events and general knowledge about the world. Usually, the events and knowledge that are “wiped out” by the treatments are those from up to a few months before the treatments begin to about a month after the treatments are done. Even more remote memories may be forgotten as well. Unlike the other types of ECT-induced memory impairment, retrograde amnesia may be permanent.
Catatonic features It has been known for decades that catatonic features, regardless of etiology, respond robustly and often quickly to a course of ECT. 1,7 But in recent years, the literature has documented the high rates of efficacy of benzodiazepines, usually lorazepam, in the initial treatment of catatonic signs such as mutism, stupor, waxy flexibility, posturing, stereotypies, and rigidity.
Bush et al 8 treated 21 acutely catatonic patients, who were so diagnosed according to a standardized catatonia rating scale, with parenteral and oral lorazepam at doses up to 8 mg/d. Sixteen responded dramatically, usually within a day or so. Four of the lorazepam nonresponders were given ECT with excellent results, not only for the catatonic signs but also for other underlying psychopathological features.
Ungvari et al 9 treated 18 catatonic patients with either lorazepam or diazepam; all patients had some degree of improvement after several days, but 9 of the 18 exhibited insufficient response. For these, ECT was administered with excellent resolution of the psychopathology, including catatonia.
A reasonable conclusion from these studies is that acutely catatonic patients should be treated first with a benzodiazepine such as parenteral and/or oral lorazepam, perhaps for up to 3 days, and then given ECT if response is insufficient. For patients with malignant catatonia—a particularly severe and life-threatening form of catatonia—ECT may need to be instituted sooner. 10
Psychotic features Though the literature has been mixed on this subject, patients with psychotic depression have high response rates to an adequate course of ECT treatments. Hickie et al 6 treated 81 depressed patients with ECT and performed in-depth analyses of a variety of clinical variables, including the presence of psychosis. Patients with psychotic depression were found to have a significantly higher rate of ECT response than those with nonpsychotic depression, though the latter still had high response rates.
- Response rates are uniformly high.
- If such patients were to receive pharmacotherapy, a neuroleptic with all the potential neurologic side effects inherent in such medication would be needed.
Further, clinical experience reveals that psychotically depressed patients tend to be particularly nonfunctional, to have lost weight, and to be suicidal. Thus, the rapid, definitive benefits of ECT are necessary as first-line therapy.
Age Age has been positively correlated with ECT outcome. Black et al, 11 in an analysis of clinical predictors of ECT in several hundred patients, found that older patients responded more favorably to ECT than did younger ones. The study included careful assessments of pre- and post-ECT clinical status.
Tew et al, 12 in a well-designed prospective study of several hundred ECT patients, found that those older than age 65 responded to ECT more favorably than those younger than 65. Possible mitigating factors in the younger group were greater medication nonresponsivity prior to ECT and longer illness severity. In another prospective study, Wilkinson et al 13 also found superior response rates in patients older than 75.
At minimum, a consensus emerges from the literature that ECT response rates are at least as good in the elderly as in younger patients, an important finding given the often debilitating effects of depressive illness in this population and the high rates of medication nonresponse.
Potential for self-harm ECT is highly effective for suicidal or cachectic individuals. Decades of clinical practice have clearly established that acutely suicidal, depressed patients and those whose poor food and fluid intake has caused nutritional compromise represent urgent indications for ECT. 1,7 In particular, recent research suggests that ECT response may be especially rapid in bipolar depressed patients. 14