Electroconvulsive Therapy (ECT)

Types of ECT

By Electrode Placement

1. Bilateral ECT (Bifrontotemporal / BFT)

• One electrode placed over each temporal region (bitemporal placement)
• Historically the most widely used configuration
• Most reliable and fastest therapeutic effect - often preferred for life-threatening illness (severe suicidality, malnutrition, catatonia)
• Associated with the most neurocognitive adverse effects - greatest retrograde amnesia and risk of delirium
• Higher risk of delirium that may require interruption of the ECT course
• Recommended to use moderately suprathreshold dosing (1.5× seizure threshold) to attenuate cognitive side effects
• Brief pulse waveform is recommended; ultrabrief pulse has not been consistently demonstrated effective with bitemporal placement

2. Right Unilateral ECT (RUL / d'Elia Placement)

• Both electrodes placed on the right (non-dominant) hemisphere
• Named after d'Elia, who developed the placement
• Requires high-dose stimulation (500-600% above seizure threshold) to match bilateral ECT in efficacy
• At 6× seizure threshold: equivalent efficacy to bilateral ECT
• Significantly better cognitive side-effect profile - less retrograde amnesia, less anterograde memory impairment
• Long-term cognitive advantages persist even at higher doses
• Now widely recommended as the first-line placement to reduce cognitive side effects
• Ultrabrief pulse RUL at 6× threshold equals brief pulse bilateral ECT in efficacy

3. Bifrontal ECT (BF)

• Both electrodes placed over the frontal regions, more anteriorly
• Introduced as a newer configuration to balance efficacy with cognitive sparing
• Seizure threshold tends to be higher than bilateral and unilateral placements
• Several studies show equivalent efficacy to bifrontotemporal and adequately-dosed RUL
• Cognitive advantages over bilateral ECT are preliminary - requires larger, better-powered studies
• More likely to produce EEG seizure without visible motor seizure - EEG monitoring is especially useful
• Asymmetric placements are also under investigation

By Stimulus Waveform

By Treatment Schedule/Type

By Anesthesia Technique (Modified vs. Unmodified)

• Modified ECT: Current standard - uses general anesthesia (typically methohexital or propofol) + succinylcholine (muscle relaxant) + atropine/glycopyrrolate (to reduce secretions). Seizure expression is attenuated; only minor motor movement visible
• Unmodified ECT: Without anesthesia or muscle relaxants - historical, now obsolete in most settings due to risk of fractures and aspiration

Indications

• Severe major depressive episode with psychotic features
• Life-threatening depression (active suicidality, refusal to eat/drink, severe inanition)
• Treatment-resistant depression (failed 2+ adequate antidepressant trials)
• Catatonia (any etiology - mood, psychotic, medical, neurologic)
• Severe mania with agitation or treatment resistance
• Depressed or suicidal pregnant women who cannot take medications safely

• Acute schizophrenia with marked positive symptoms or affective features (not chronic schizophrenia)
• Neuroleptic malignant syndrome (NMS)
• Parkinson disease (on-off phenomenon)
• Intractable seizure disorders
• Severe depression in elderly or medically ill patients who cannot tolerate antidepressants

Side Effects

Cognitive / Neurological

Cardiovascular

• Bradycardia (vagal response to stimulus) - can be severe; prevented with atropine premedication
• Tachycardia and hypertension - sympathetic surge during and after the seizure
• Arrhythmias - brief, usually self-limiting
• Cardiac risk is greatest in patients with pre-existing heart disease; ECT can still be administered in cardiac patients with careful monitoring

Other Physical

Advantages

1. Highest efficacy for major depression - Response rates of 70-90%, far exceeding pharmacotherapy (50-60%)
2. Rapid onset - Clinical response begins after 1-2 treatments; full response often within 1-2 weeks - invaluable in life-threatening presentations
3. Effective when medications fail - Works in treatment-resistant cases that have failed multiple antidepressants
4. Safe in special populations - Can be used in pregnancy (when medications are unsafe), elderly, and medically ill patients who cannot tolerate pharmacotherapy
5. Safe with physical illness - Carefully administered ECT is often safer than high-dose pharmacotherapy in frail elderly patients
6. Effective for catatonia - Often the only treatment for life-threatening catatonic states
7. No cumulative organ toxicity - Unlike long-term medication use, ECT does not cause hepatic, renal, or cardiac toxicity from drug accumulation
8. Adjustable cognitive risk - By choosing RUL + ultrabrief pulse + dose titration, cognitive side effects can be minimized while maintaining efficacy

Disadvantages

1. Cognitive side effects - Memory impairment (especially retrograde amnesia) is the most stigmatized limitation; though usually reversible, it causes significant distress to some patients
2. Requires general anesthesia - Adds procedural risk, logistics, and cost; requires NPO status and anesthesia team
3. Stigma - Public perception (influenced by media portrayals) creates fear and resistance among patients and families
4. Relapse without maintenance - Without continuation/maintenance pharmacotherapy or ECT, relapse rates are high (>50% within 6-12 months)
5. Not a cure - Treats acute episodes but does not resolve the underlying disorder; requires ongoing treatment
6. Logistical burden - Multiple visits (3×/week) require transport, time off work, and sometimes hospitalization
7. Contraindications/precautions - Space-occupying lesions with raised ICP (not absolute, but high risk), recent MI or unstable angina, high anesthetic risk
8. Limited access - Not available in all hospitals; concentrated in academic medical centers and private institutions
9. Drug interactions - Several medications must be stopped before ECT (benzodiazepines, lithium, clozapine, bupropion, lidocaine, theophylline, reserpine) creating management challenges

Contraindications and Key Drug Interactions

• Benzodiazepines - anticonvulsant activity reduces seizure induction; must be tapered/stopped
• Lithium - increases postictal delirium and can prolong seizure; must be stopped
• Clozapine / Bupropion - associated with late-appearing seizures
• Theophylline - prolongs seizure duration dangerously
• Reserpine - compromises respiratory and cardiovascular function during ECT
• Lidocaine - markedly raises seizure threshold (makes ECT ineffective)

Summary Comparison Table: ECT Types

• Kaplan and Sadock's Synopsis of Psychiatry, Chapter 22 (ECT)
• Kaplan & Sadock's Comprehensive Textbook of Psychiatry, Chapter 55 (ECT Parameters & Neurocognitive Effects)