What is the role of electroconvulsive therapy (ECT) in treating severe, treatment-resistant depression in patients who have not responded to multiple antidepressant medications?

ECT for Treatment-Resistant Depression

Electroconvulsive therapy is a highly effective treatment for severe, treatment-resistant depression and should be considered after failure of two adequate antidepressant trials, though it may be used as first-line therapy when symptoms are life-threatening. 1, 2

Primary Indications for ECT in Depression

ECT is indicated for severe, persistent major depression, particularly when:

• Life-threatening symptoms are present, including refusal to eat or drink, severe suicidality, or profound psychomotor retardation 1, 2
• Psychotic features accompany the depression, as ECT shows greatest benefit in this population 3
• Patients are aged 45 years or older, where ECT demonstrates enhanced efficacy 3
• Two or more adequate antidepressant trials have failed (8-10 weeks at therapeutic doses with confirmed adherence) 1

Treatment-Resistant Depression Criteria

Before considering ECT, confirm true treatment resistance by ensuring:

• Adequate trial duration: At least 8-10 weeks per antidepressant at therapeutic doses 1
• Medication adherence: Verify through pill counts, serum levels, or supervised administration, as noncompliance is common 1
• Two distinct medication classes have failed for unipolar depression 1
• Appropriate severity: Symptoms must be severe, persistent, and significantly disabling 1, 2

Important caveat: The requirement for two failed trials can be bypassed when waiting endangers the patient's life or when medication intolerance prevents adequate trials 1, 2

Efficacy and Outcomes

ECT demonstrates superior effectiveness compared to continued pharmacotherapy:

• Remission rates of 48-65% even in medication-resistant patients, with higher rates (65%) in those without prior medication failures 3
• 50% reduction in suicide risk in the first year post-discharge compared to patients not receiving ECT 3, 4
• Rapid response, often within the first 5-6 treatments of a typical 10-12 treatment course 3
• Most effective acute treatment for severe mood disorders according to established evidence 5

Treatment Protocol

Standard administration approach:

• Frequency: Three times weekly in most centers (twice weekly is acceptable) 3
• Course length: 10-12 treatments typically, with initial improvement after 5-6 sessions 3
• Electrode placement: Bilateral placement may be preferred initially for severe agitated depression to achieve more rapid response, though right unilateral placement has equivalent efficacy with fewer cognitive side effects 3, 6

Medication Management During ECT

Discontinue before ECT:

• Lithium, benzodiazepines, and carbamazepine due to adverse effect risks 3

May continue during ECT:

• Olanzapine and mirtazapine as part of maintenance strategy 3
• Vortioxetine and other antidepressants unless specific side effects emerge, as they may prevent relapse post-ECT 3

Contraindications

There are no absolute contraindications to ECT 1, 4, 2. Conditions previously considered contraindications are now only relative concerns:

• Cerebral tumors, recent myocardial infarction, and active chest infections are not absolute contraindications 1
• Renal impairment (including lithium-induced) does not preclude ECT 4
• Seizure disorders may actually improve with ECT 2
• Personality disorders and cognitive impairment do not contraindicate use 3, 2

Post-ECT Management

Continuation treatment is essential to prevent relapse:

• Pharmacotherapy tailored to the presenting disorder should be initiated 2
• Maintenance ECT may be necessary for severely and recurrently depressed patients who respond only to ECT 7
• Close monitoring of cognitive function is required, as memory impairment may persist approximately 2 months post-treatment 2

Common Pitfalls to Avoid

• Do not delay ECT in life-threatening situations waiting for additional medication trials 1, 2
• Verify medication adherence before labeling depression as treatment-resistant, as noncompliance rates are high 1
• Do not reserve ECT as last resort; consider it based on individual patient and illness factors 8
• Ensure adequate seizure induction through proper threshold determination, as suboptimal technique reduces efficacy 7
• Plan for continuation treatment before starting ECT, as relapse rates are high without maintenance therapy 2, 7