My answer is in 3 parts: my professional experience with ECT and my perspective on its use, a list of articles and book references for efficacy studies, and a great list of the current understanding of possible mechanisms of action.
Professional Experience with ECT:
I was required in my psychiatric rotation in med school 2 years ago to assist with ECT therapy sessions. I had a lot of concerns about ECT myself, so I did a lot of reading about ECT - before I felt I could ethically assist with the procedures. My attending physician (an expert in the field and strong advocate for ECT) gave me some resources, and then I searched for my own (to avoid his bias). After reading, I was surprised about the efficacy results in studies, and with my gained understanding of current knowledge on mechanism of action, I felt comfortable in assisting.
I assisted with several ECT sessions in an extended inpatient setting. A patient whom I was following responded very well to it, after years of failed antidepressant therapy and suicide attempts. I followed her only over 10 days, so I can't personally say I witnessed her improvement past that date. Many patients were kept on their antidepressant/ antipsychotic medication regimen, and ECT was a supplement. Other patients who were completely unable to tolerate psychotropic medications, so ECT was their only medical option (outside of alternative medicine etc., which I do not know enough about to make comparisons).
To be honest, for long-term efficacy versus antidepressant therapy, I didn't find a lot of data when I looked. It would take a more in-depth PubMed search. I plan to keep my eye out, because although it's not something I prescribe, I would like to understand it more deeply. Let me know if you find something!
Clinical Guidelines: Source UpToDate - a clinical practice database of peer-reviewed evidence-based current best practice guidelines and information.
Research Articles: Source PubMed
Efficacy and safety of electroconvulsive therapy in depressive disorders: a systematic review and meta-analysis.
AUUK ECT Review Group, SOLancet. 2003;361(9360):799.
BACKGROUND: We aimed to review published work for the efficacy and safety of electroconvulsive therapy (ECT) with simulated ECT, ECT
versus pharmacotherapy, and different forms of ECT for patients with
METHODS**strong text**ODS: We designed a **systematic overview and meta-analysis of randomised controlled trials and observational
studies. We obtained data from the Cochrane Collaboration Depressive
Anxiety and Neurosis and Schizophrenia Group Controlled trial
registers, Cochrane Controlled Trials register, Biological Abstracts,
CINAHL, EMBASE, LILACS, MEDLINE, PsycINFO, and SIGLE, reference lists,
and specialist textbooks. Our main outcome measures were depressive
symptoms, measures of cognitive function, and mortality.
FINDINGS: Meta-analysis of data of short-term efficacy from randomised controlled trials was possible. Real ECT was significantly
more effective than simulated ECT (six trials, 256 patients,
standardised effect size [SES]-0.91, 95% CI -1.27 to -0.54). Treatment
with ECT was significantly more effective than pharmacotherapy (18
trials, 1144 participants, SES -0.80, 95% CI -1.29 to -0.29).
Bilateral ECT was more effective than unipolar ECT (22 trials, 1408
participants, SES -0.32, 95% CI -0.46 to -0.19).
INTERPRETATION: ECT is an effective short-term treatment for depression, and is probably more effective than drug therapy.
Bilateral ECT is moderately more effective than unilateral ECT, and
high dose ECT is more effective than low dose.
A meta-analysis of electroconvulsive therapy efficacy in depression.
AUKho KH, van Vreeswijk MF, Simpson S, Zwinderman AH
SOJ ECT. 2003;19(3):139. PMID12972983
SUMMARY: Recently published controlled studies comparing
electroconvulsive therapy (ECT) with other treatments for depression
offer the opportunity to perform a meta-analysis of ECT in depression.
Fifteen studies were identified which fulfilled the inclusion
criteria. From these controlled trials, 20 effect sizes of ECT were
calculated. The speed of action during the course and the efficacy
after a full course of ECT were explored. The efficacy of sine wave
and brief pulse machines were compared. The comparison between ECT and
four other comparative treatments was made. Predictive variables were
explored using homogeneity tests.
ECT was shown to be superior after a
full course. The funnel plot showed the absence of publication bias.
There was no exaggeration of effect size in the lower quality trials.
No evidence was found for a superior speed of action of ECT or for a
difference in efficacy between sine wave and brief pulse stimulation.
ECT was shown to be superior to medication and simulated ECT. Some
evidence was found that psychosis predicted better response to ECT.
Delfland, Locatie St Jorisweg, 2 Delft, The Netherlands. email@example.com
Efficacy of ECT in depression: a meta-analytic review.
AUPagnin D, de Queiroz V, Pini S, Cassano GB
SOJ ECT. 2004;20(1):13.
This study analyzed the efficacy of electroconvulsive therapy (ECT) in
depression by means a meta-analytic review of randomized controlled
trials that compared ECT with simulated ECT or placebo or
antidepressant drugs and by a complementary meta-analytic review of
nonrandomized controlled trials that compared ECT with antidepressants
The review revealed a significant superiority of ECT in all
comparisons: ECT versus simulated ECT, ECT versus placebo, ECT versus
antidepressants in general, ECT versus TCAs and ECT versus MAOIs. The
nonrandomized controlled trials also revealed a significant
statistical difference in favor of ECT when confronted with
antidepressants drugs. Data analyzed suggest that ECT is a valid
therapeutic tool for treatment of depression, including severe and
Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology. University of Pisa, Italy. firstname.lastname@example.org
Mechanisms of Action
There are still uncertainties of exactly what among the physiological effects of ECT is directly responsible for mood alteration, but UpToDate has a great breakdown of the mechanisms:
MECHANISM OF ACTION — The mechanism of action for ECT is unknown, but
there are many well-documented changes in the central nervous system:
Human and animal studies show that ECT increases release of monoamine
neurotransmitters, particularly dopamine and serotonin [8-10]. ECT
also enhances monoamine transmission by desensitizing presynaptic
One theory postulates that ECT exerts its
beneficial effects by increasing release of central neuropeptides,
including corticotrophin releasing factor, somatostatin (STS), and
neuropeptide Y .
The neuroendocrine hypothesis is based upon the
diabetes/insulin model and suggests that mood disorders are caused by
insufficiency of a hypothalamic mood-maintaining peptide .
Repeated seizures enhance the production and release of the putative
hypothalamic peptide antidepression, which relieves both
neuroendocrine and behavioral abnormalities.
ECT has anticonvulsant
properties (perhaps related to enhanced gamma-aminobutyric acid
transmission), which has led to the suggestion that these properties
are responsible for the therapeutic effects of the treatment .
Positron emission tomography (PET) studies demonstrate decreased
metabolic activity in frontal and cingulate cortex after ECT .
Functional magnetic resonance imaging before and after successful
treatment with ECT reveals a reduction in global connectivity within
the left dorsal lateral prefrontal cortex .
electroencephalogram (EEG) studies demonstrate increased slow (delta)
wave activity in the prefrontal cortex after ECT, which is associated
with clinical response .
Several human and animal studies indicate
that ECT has trophic effects on the central nervous system [17-21].
ECT increases brain derived neurotrophic factor (BDNF) in patients and
electroconvulsive stimulation induces neurogenesis and mossy fibre
sprouting from granule cells in rat hippocampus.
Finally, the book chapter that I read is called "Hypothesized Mechanisms and Sites of Actions of Electroconvulsive Therapy" by Nikolaus Michael in the book Electroconvulsive and Neuromodulation Therapies by Conrad M. Swartz MD. Very technical but very interesting!