Hypophyseal response to ECT: a higher and faster vasopressin peak

Molecular Biomarkers of Electroconvulsive Therapy Effects and Clinical Response: Understanding the Present to Shape the Future

Electroconvulsive therapy (ECT) represents an effective intervention for treatment-resistant depression (TRD). One priority of this research field is the clarification of ECT response mechanisms and the identification of biomarkers predicting its outcomes. We propose an overview of the molecular studies on ECT, concerning its course and outcome prediction, including also animal studies on electroconvulsive seizures (ECS), an experimental analogue of ECT. Most of these investigations underlie biological systems related to major depressive disorder (MDD), such as the neurotrophic and inflammatory/immune ones, indicating effects of ECT on these processes. Studies about neurotrophins, like the brain-derived neurotrophic factor (BDNF) and the vascular endothelial growth factor (VEGF), have shown evidence concerning ECT neurotrophic effects. The inflammatory/immune system has also been studied, suggesting an acute stress reaction following an ECT session. However, at the end of the treatment, ECT produces a reduction in inflammatory-associated biomarkers such as cortisol, TNF-alpha and interleukin 6. Other biological systems, including the monoaminergic and the endocrine, have been sparsely investigated. Despite some promising results, limitations exist. Most of the studies are concentrated on one or few markers and many studies are relatively old, with small sample sizes and methodological biases. Expression studies on gene transcripts and microRNAs are rare and genetic studies are sparse. To date, no conclusive evidence regarding ECT molecular markers has been reached; however, the future may be just around the corner.

Prolactin changes during electroconvulsive therapy: A systematic review and meta-analysis

BACKGROUND

Early studies reported a prolactin surge during electroconvulsive therapy (ECT). The aim of this study is to review and meta-analyze data on ECT-related prolactin changes.

METHOD

A systematic review and meta-analysis was conducted for trials investigating prolactin changes in ECT-treated patients using standard mean differences (SMD, 95% confidence intervals). Subgroup analyses included comparisons of ECT-related prolactin changes in women vs. men, patients receiving different anesthetics, bilateral vs. unilateral and high-vs. low-dose ECT.

RESULTS

In six trials including 109 ECT-treated patients and 74 controls, prolactin changes were larger in ECT-treated patients than in controls (SMD = 0.89, 95%CI = 0.55, 1.23, p < 0.001 and 1.03, 95%CI = 0.31, 1.75, p = 0.005 for the fixed and random-effect model respectively), despite heterogeneity in the samples (I² = 72%, τ² = 0.62). Effects were led by differences in patients premedicated with methohexital (SMD = 1.14, 95%CI = 0.7, 1.57, p < 0.001 for both fixed and random-effect model). A meta-regression reported significant age effects (coefficient estimate 2.32, 95%CI = -0.73, 3.91, p < 0.01). Additionally, prolactin changes were larger in ECT-treated women than men (SMD = 0.88, 95%CI = 0.58, 1.18, p < 0.001 and 0.99, 95%CI = 0.22, 1.75, p = 0.012 for the fixed and random effect model). Bilateral ECT-treated patients had larger increase than unilateral ECT-treated patients (SMD = -0.81, 95%CI = -1.35, -0.27, p = 0.003 and -0.86, 95%CI = -1.46, -0.25, p = 0.006 for the fixed and random-effect model). Comparisons between high- and low-dose ECT-treated patients could not be conducted. The quality of the studies was overall poor, with four exceptions.

DISCUSSION

Patients receiving ECT had larger prolactin increases than controls. Increases were larger in methohexital-premedicated patients, women vs. men and patients with bilateral vs. unilateral ECT.

Electroconvulsive Treatment: Hypotheses about Mechanisms of Action

No consensus has been reached on the mode of action of electroconvulsive treatment (ECT). We suggest that two features may aid in the delineation of the involved mechanisms. First, when effective, ECT would be likely to affect brain functions that are typically altered in its primary recipient group, people with severe depression. Central among these are the frontal and temporal lobes, the hypothalamus-pituitary-adrenal (HPA) stress axis, and the mesocorticolimbic dopamine system. Second, the involved mechanisms should be affected for a time period that matches the average endurance of clinical effects, which is indicated to be several days to a few weeks. To identify effects upon frontal and temporal lobe functioning we reviewed human studies using EEG, PET, SPECT, and fMRI. Effects upon the HPA axis and the dopamine system were assessed by reviewing both human and animal studies. The EEG studies indicate that ECT decelerates neural activity in the frontal and temporal lobes (increased delta and theta wave activity) for weeks to months. Comparable findings are reported from PET and SPECT studies, with reduced cerebral blood flow (functional deactivation) for weeks to months after treatment. The EEG deceleration and functional deactivation following ECT are statistically associated with reduced depression scores. FMRI studies indicate that ECT flattens the pattern of activation and deactivation that is associated with cognitive task performance and alters cortical functional connectivity in the ultra slow frequency range. A common finding from human and animal studies is that ECT acutely activates both the HPA axis and the dopamine system. In considering this evidence, we hypothesize that ECT affects the brain in a similar manner as severe stress or brain trauma which activates the HPA axis and the dopamine system and may compromise frontotemporal functions.

Blood concentrations of vasopressin, neuropeptide FF and prolactin are increased by high-dose right unilateral ECT

Electroconvulsive therapy (ECT) is known to stimulate subcortical brain regions and release hormones from the anterior and the posterior pituitary. To enhance the subcortical effect of ECT and the neuroendocrinological response we used high dose right unilateral ECT (RUL-ECT) in 11 depressive patients and studied its effect on the release of vasopressin, prolactin and neuropeptide FF. The RUL ECT stimulus for all studied patients was 5 times the individual seizure threshold and it led to immediate release of vasopressin in all studied patients. The release of prolactin was less uniform however in accordance with results from earlier studies. The ECT also stimulated a NPFF secretion peak that came approximately 5 min after ECT stimulus and preceded the prolactin peak. The maximal elevations in circulating vasopressin and prolactin concentrations were 680% and 950%, respectively. The neuropeptide FF concentration increased by 100% after ECT. There was a second rise in NPFF concentration at 25 min after the ECT treatment. The increases in all peptide concentrations were significant, but were not correlated with each other. The neuropeptide FF concentration returned to baseline level at 10 min and the vasopressin concentration at 25 min after ECT. The prolactin concentration remained increased during the 30 min follow up period. Our results complete earlier finding on ECT stimulated vasopressin and prolactin release and show that high intensity RUL-ECT releases neuropeptide FF into human blood. The modest rise of circulating NFFF most likely represents leakage from the CNS.

Effects of electroconvulsive therapy on plasma vasopressin and oxytocin

BACKGROUND

Animal studies suggest that vasopressin has cognitive-enhancing properties and oxytocin may have amnestic effects. A clinical report suggests that the acute increase in oxytocin-associated neurophysin predicts clinical response to electroconvulsive therapy (ECT) in depressed patients.

METHODS

Medication-free patients with major depression were randomized to receive right unilateral or bilateral ECT administered with electrical stimulus intensity at either just above seizure threshold or at 150% above seizure threshold. The associations between plasma vasopressin, oxytocin, ECT treatment parameters, clinical outcome, and cognitive effects were assessed.

RESULTS

The sample comprised 55 patients. At the second ECT, patients receiving ECT at 150% above initial seizure threshold had significantly greater increases in plasma vasopressin than patients receiving low-dose ECT (ps < .01-.04), with no effects of electrode placement. At the second and ninth ECT treatments, the vasopressin or oxytocin surges were not associated with clinical improvement, seizure duration, time to orientation, or memory test performance. There were inverse trend-level associations between the acute surge in oxytocin levels at the ninth ECT and clinical response, contradicting a report in the literature.

CONCLUSIONS

Overall, these findings do not support the hypothesis that diencephalic seizure propagation is central to the mechanism of action of ECT.