Remission of melancholia is achieved in 80–95% of patients treated with electroconvulsive therapy (ECT). Lesser remission rates, however, are commonly reported. What accounts for the differences in clinical outcome?

The technical practice of ECT is complex and not all treatment courses are optimized to assure the maximum therapeutic benefit. Inappropriate frequency and inadequate numbers of treatments, energies too low to assure an effective seizure, elevated seizure thresholds, inefficient electrode placements, and missed or incomplete seizures result in courses of treatment with limited benefit.

Patient selection

Convulsive therapy relieves depressive mood disorders, yet the benefits are best established in those with melancholia. The relief of severe disorders in mood was discovered early in ECT history. In patients with both the depressed and manic phases of “manic-depressive insanity” and “involutional depression,” the introduction of ECT was quickly identified as a life-saving treatment. To assure proper selection of patients, an intensive search for predictors of good response examined identifiable symptoms and syndromes, demographic features, severity of illness, and duration of illness. An excellent and rapid clinical response found in melancholia of recent onset with severe vegetative signs, suicide intent, and delusional thinking occurred in older rather than younger patients. A poor outcome was associated with chronic illness, limited impairment that allowed sustained employment, comorbid personality disorder, “neurotic symptoms” (pervasive anxiety, dysthymia, hypochondriasis), and substance abuse. Specific behavior-rating scales designed as predictors were developed.

Melancholia is a severely debilitating illness with a high death rate and high potential for suicide. Its consequences were so dire that the introduction of even so intrusive a treatment as induced seizures was hailed as a remarkable advance. Over the past half-century, medications effective in ameliorating melancholia were developed and the fears that melancholia engendered in earlier centuries lessened.

Our present therapeutic ideal is to select treatments based on scientific study, defined as evidence-based medicine. Randomized controlled clinical trials form the foundation of evidence-based medicine, and the literature assessing the benefits of antidepressant and mood-stabilizing drugs is widely accepted. Reviews of this evidence conclude that all antidepressant medications have equal efficacy for major depression, differing only in side-effects. These conclusions influence clinical guidelines.

Present teaching, as expressed by an expert National Institutes of Mental Health (NIMH) panel states that: “The SSRIs [selective serotonin reuptake inhibitors] are clearly the drug treatment of choice for all forms of depression in the United States … These drugs are approximately equivalent to each other and to TCAs [tricyclic antidepressants] in efficacy … The SSRIs have a much more benign side effect profile than TCAs and, largely for this reason, have replaced TCAs as first line therapy.”