Bitemporal v. high-dose right unilateral electroconvulsive therapy for depression: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Brief-pulse electroconvulsive therapy (ECT) is the most acutely effective treatment for severe depression though concerns persist about cognitive side-effects. While bitemporal electrode placement is the most commonly used form worldwide, right unilateral ECT causes less cognitive side-effects though historically it has been deemed less effective. Several randomized trials have now compared high-dose (>5× seizure threshold) unilateral ECT with moderate-dose (1.0-2.5× seizure threshold) bitemporal ECT to investigate if it is as effective as bitemporal ECT but still has less cognitive side-effects. We aimed to systematically review these trials and meta-analyse clinical and cognitive outcomes where appropriate.

METHOD

We searched PubMed, PsycINFO, Web of Science, Cochrane Library and EMBASE for randomized trials comparing these forms of ECT using the terms 'electroconvulsive' OR 'electroshock' AND 'trial'.

RESULTS

Seven trials (n = 792) met inclusion criteria. Bitemporal ECT did not differ from high-dose unilateral ECT on depression rating change scores [Hedges's g = -0.03, 95% confidence interval (CI) -0.17 to 0.11], remission (RR 1.06, 95% CI 0.93-1.20), or relapse at 12 months (RR 1.42, 95% CI 0.90-2.23). There was an advantage for unilateral ECT on reorientation time after individual ECT sessions (mean difference in minutes = -8.28, 95% CI -12.86 to -3.70) and retrograde autobiographical memory (Hedges's g = -0.46, 95% CI -0.87 to -0.04) after completing an ECT course. There were no differences for general cognition, category fluency and delayed visual and verbal memory.

CONCLUSIONS

High-dose unilateral ECT does not differ from moderate-dose bitemporal ECT in antidepressant efficacy but has some cognitive advantages.

When less is more--microRNAs and psychiatric disorders

OBJECTIVE

MicroRNAs are small non-coding RNA molecules that regulate gene expression, including genes involved in neuronal function and plasticity that have relevance for brain function and mental health. We therefore performed a systematic review of miRNAs in general adult psychiatric disorders.

METHOD

Systematic searches in PubMed/MEDLINE and Web of Science were conducted to identify published clinical articles on microRNAs in general adult psychiatric disorders. We also reviewed references from included articles.

RESULTS

There is mounting evidence of microRNAs' regulatory roles in a number of central nervous system processes, including neurogenesis and synaptic plasticity. The majority of clinical studies of microRNAs in psychiatric disorders are in schizophrenia, where a number of specific microRNAs have been identified in separate studies. There is some evidence of marked downregulation of some microRNAs in affective disorders. Treatment with antidepressants appears to upregulate microRNA levels. There is currently little evidence from human studies in anxiety, addiction or other psychiatric disorders.

CONCLUSION

MicroRNA research in psychiatry is currently in a nascent period, but represents an emerging and exciting area, with the potential to clarify molecular mechanisms of disease and identify novel biomarkers and therapeutic agents.

Peripheral blood microRNA and VEGFA mRNA changes following electroconvulsive therapy: implications for psychotic depression

OBJECTIVE

MicroRNAs are short, non-coding molecules that regulate gene expression. Here, we investigate the role of microRNAs in depression and electroconvulsive therapy (ECT).

METHODS

We performed three studies: a deep sequencing discovery-phase study of miRNA changes in whole blood following ECT (n = 16), followed by a validation study in a separate cohort of patients pre-/post-ECT (n = 37) and matched healthy controls (n = 34). Changes in an experimentally validated gene target (VEGFA) were then analysed in patients pre-/post-ECT (n = 97) and in matched healthy controls (n = 53).

RESULTS

In the discovery-phase study, we found no statistically significant differences in miRNA expression from baseline to end of treatment in the group as a whole, but post hoc analysis indicated a difference in patients with psychotic depression (n = 3). In a follow-up validation study, patients with psychotic depression (n = 7) had elevated baseline levels of miR-126-3p (t = 3.015, P = 0.006) and miR-106a-5p (t = 2.598, P = 0.025) compared to healthy controls. Following ECT, these differences disappeared. Baseline VEGFA levels were significantly higher in depressed patients compared to healthy controls (F(1,144) = 27.688, P = <0.001). Following ECT, there was a significant change in VEGFA levels in the psychotic group only (t = 2.915, P = 0.010).

CONCLUSION

Molecular differences (miRNA and VEGFA) may exist between psychotic and non-psychotic depression treated with ECT.

Electroconvulsive therapy modulates plasma pigment epithelium-derived factor in depression: a proteomics study

Electroconvulsive therapy (ECT) is the most effective treatment for severe depression, yet its mechanism of action is not fully understood. Peripheral blood proteomic analyses may offer insights into the molecular mechanisms of ECT. Patients with a major depressive episode were recruited as part of the EFFECT-Dep trial (enhancing the effectiveness of electroconvulsive therapy in severe depression; ISRCTN23577151) along with healthy controls. As a discovery-phase study, patient plasma pre-/post-ECT (n=30) was analyzed using 2-dimensional difference in gel electrophoresis and mass spectrometry. Identified proteins were selected for confirmation studies using immunodetection methods. Samples from a separate group of patients (pre-/post-ECT; n=57) and matched healthy controls (n=43) were then used to validate confirmed changes. Target protein mRNA levels were also assessed in rat brain and blood following electroconvulsive stimulation (ECS), the animal model of ECT. We found that ECT significantly altered 121 protein spots with 36 proteins identified by mass spectrometry. Confirmation studies identified a post-ECT increase (P<0.01) in the antiangiogenic and neuroprotective mediator pigment epithelium-derived factor (PEDF). Validation work showed an increase (P<0.001) in plasma PEDF in depressed patients compared with the controls that was further increased post-ECT (P=0.03). PEDF levels were not associated with mood scores. Chronic, but not acute, ECS increased PEDF mRNA in rat hippocampus (P=0.02) and dentate gyrus (P=0.03). This study identified alterations in blood levels of PEDF in depressed patients and further alterations following ECT, as well as in an animal model of ECT. These findings implicate PEDF in the biological response to ECT for depression.