Can ECT-induced cognitive effects be altered pharmacologically?

Efficacy and Side Effects of Mixed-Strategy Electroconvulsive Therapy: A Proof-of-Concept Randomized Clinical Trial on Late Life Depression

OBJECTIVE

Patients with late life depression sometimes refuse to receive electroconvulsive therapy (ECT) owing to its adverse reactions. To alleviate patient's resistance, a novel ECT stimulation strategy named mixed-strategy ECT (msECT) was designed in which patients are administered conventional ECT during the first three sessions, followed by low energy stimulation during the subsequent sessions. However, whether low energy electrical stimulation in the subsequent stage of therapy affect its efficacy and reduce adverse reactions in patients with late life depression remains unknown. To explore differences between msECT and regular ECT(RECT) with respect to clinical efficacy and side effects.

METHODS

This randomized, controlled trial was conducted from 2019 to 2021 on 60 patients with late life depression who were randomly assigned to two groups: RECT or msECT. A generalized estimating equation (GEE) was used to compare the two stimulation strategies regarding their efficacy and side effects on cognition. Chi-squared test was used to compare side effects in the two strategies.

RESULTS

In the intent-to-treat group, the GEE model suggested no differences between-group difference in Hamilton Depression Rating Scale-17 score over time (Wald χ2=7.275, p=0.064), whereas the comparison of side effects in the two strategies favored msECT (Wald χ2=8.463, p=0.015) as fewer patients had adverse events during the second phase of treatment with msECT (χ2 =13.467, p=0.004).

CONCLUSION

msECT presents its similar efficacy to RECT. msECT may have milder side effects on cognition.

Prophylactic cognitive enhancers for improvement of cognitive function in patients undergoing electroconvulsive therapy: A systematic review and meta-analysis

OBJECTIVE

Cognitive enhancers, including cholinesterase inhibitors and memantine, are used to treat dementia, but their effect for reducing post-electroconvulsive therapy (post-ECT) cognitive side effects is unclear. We conducted a systematic review and meta-analysis to assess the effectiveness of cognitive enhancers in the prevention of cognitive side effects due to ECT.

METHODS

We identified relevant studies by searching electronic databases (e.g., PubMed, EMBASE, Web of Science, Cochrane Library). Only studies published up to October 2019 comparing cognitive enhancer vs placebo for cognitive function after ECT were included. The primary outcome extracted from the studies was cognitive function score.

RESULTS

Five studies with 202 patients were included in this study. The cognitive enhancer group (CEG) had a significantly higher cognitive function score. Moreover, sensitivity analysis showed that no individual study had a significant impact on the overall results.

CONCLUSIONS

This meta-analysis revealed that cognitive enhancers might improve cognitive function and reduce ECT-induced cognitive side effects. Nevertheless, more high-quality randomized controlled trials (RCTs) with long-term follow-up are still needed to make the final conclusion.

Memory and cognitive effects of ECT: informing and assessing patients†

Over the past few years electroconvulsive therapy (ECT) has come under increased scrutiny in the UK, with the first systematic review of patients' experiences and new national guidelines. Our aim in this article is to translate recent and sometimes confusing research and policy statements into practical guidance that benefits patients. We examined the evidence on the permanent memory and cognitive effects of ECT, with a focus on delineating their nature, understanding how ECT may cause them, informing prospective patients about them, and assessing their impact on former patients. We describe a simple and effective method for assessing retrograde amnesia. Data do not exist at this time to confirm the mechanisms by which ECT exerts its adverse effects, but clinicians should fully inform patients of the possible permanent adverse effects of the treatment, which include amnesia, memory disability and cognitive disability, and should provide follow-up testing using relevant instruments.

Pharmacogenetics in electroconvulsive therapy and adjunctive medications

Electroconvulsive therapy (ECT) has shown apparent efficacy in treatment of patients with depression and other mental illnesses who do not respond to psychotropic medications or need urgent control of their symptoms. Pharmacogenetics contributes to an individual's sensitivity and response to a variety of drugs. Clinical insights into pharmacogenetics of ECT and adjunctive medications not only improves its safety and efficacy in the indicated patients, but can also lead to the identification of novel treatments in psychiatric disorders through understanding of potential molecular and biological mechanisms involved. In this review, we explore the indications of pharmacogenetics role in safety and efficacy of ECT and present the evidence for its role in patients with psychiatric disorders undergoing ECT.

Pharmacological attenuation of electroconvulsive therapy--induced cognitive deficits: theoretical background and clinical findings

Electroconvulsive therapy (ECT) is an effective treatment for depression and other psychiatric disorders. However, the practice of ECT is limited by memory and nonmemory cognitive adverse effects. Technical strategies such as a preference for unilateralover bilateral ECT and low-dose over high-dose stimulation reduce these cognitive adverse effects but may also be associated with lesser treatment efficacy or slower treatment response. This article therefore reviews the use of psychopharmacological agents in the attenuation of ECT-induced cognitive deficits with 2 objectives: the identification of implicated mechanisms and the identification of putative efficacy in both animal and human studies. Drugs examined include N-methyl-d-aspartate receptor antagonists, cyclooxygenase inhibitors, calcium channel blockers, cholinesterase inhibitors, glucocorticoid receptor antagonists, thyroid hormones, opioid antagonists, NO donors, nootropic agents, and other medications. Although the clinical data at present are sparse and inconsistent, many recently opened lines of research improve our understanding of the mechanisms involved as well as suggest possible avenues for the testing of new treatments with the potential to attenuate the cognitive adverse effects of ECT.

Neurobiological correlates of the cognitive side effects of electroconvulsive therapy

Although electroconvulsive therapy (ECT) is a highly effective form of treatment, its use is limited by the emergence of cognitive side effects, notably anterograde and retrograde amnesia. Despite a large literature on the neurobiology of therapeutic mechanisms of ECT, very little is known about the neurobiological underpinnings of its cognitive effects. On theoretical grounds, structures within the medial temporal lobes, especially the hippocampus, are predicted to be critical regions mediating anterograde and, possibly, retrograde amnesia. However, functional neuroimaging studies in normal volunteers have demonstrated that frontal cortical regions are also involved in human memory processes. This review will highlight some of the biochemical, electrophysiological, and neuroimaging correlates of the amnestic side effects of ECT. In terms of electrophysiological and functional imaging studies, there are data that implicate both medial temporal and frontal regions as being associated with cognitive dysfunction. Interestingly, such data also appear to indicate a dissociation of the neural systems critical to the efficacy and adverse cognitive effects of ECT.

Effect of piracetam on ECT-induced cognitive disturbances: a randomized, placebo-controlled, double-blind study

Electroconvulsive therapy (ECT) is still the fastest, most effective, and frequently life-saving therapeutic intervention in several forms of depression and some other psychiatric disorders. Transient memory disturbances are frequent after ECT. A randomized, double-blind, placebo-controlled study was conducted to investigate the effects of piracetam on ECT-induced confusion and memory disturbances. Thirty-eight consecutively admitted patients with depressive illness or schizophrenia requiring ECT were given either piracetam or an identical-looking placebo during the period of ECT treatment and for 2 weeks afterward. Daily dosage of piracetam was 7.2 g, given orally for the first 2 weeks while patients underwent ECT (loading phase), followed by 4.8 g for the rest of the study period. Participants were evaluated by standardized clinical rating scales and cognitive psychologic tests 1 to 2 days before ECT, 1 day after their third and sixth ECT treatments, and 2 weeks after they had completed their ECT courses. Piracetam had no significant effect in preventing ECT-induced memory disturbances. All clinical ratings were consistently, albeit not significantly, better in the piracetam group, suggesting that piracetam may have augmented the effects of ECT.

Subtypes of memory dysfunction associated with ECT: characteristics and neurobiological bases

Electroconvulsive therapy (ECT) is an effective treatment for a variety of psychiatric syndromes. However, one of its adverse secondary effects is neurocognitive dysfunction. The aim of this paper is to review different subtypes of memory dysfunction associated with ECT from a neuropsychological perspective. Declarative memory is clearly impaired after ECT. Immediate memory, however, is broadly preserved. Few studies have addressed procedural and incidental memory. Selective memory is impaired, probably due to the disruption of specific brain regions. Some of the possible neurobiological bases of ECT memory dysfunction are discussed in this paper. Synaptic plasticity, the cerebral neurotransmission system, and cerebral metabolism are examined in relation to the dysfunction and subsequent recovery of each memory subtype.

Nicardipine improves the antidepressant action of ECT but does not improve cognition

INTRODUCTION

Cognitive impairment, the most important adverse effect of electroconvulsive therapy (ECT), may involve elevated intracellular calcium ion signaling. Animal research suggests that calcium channel-blocking agents, which attenuate excessive intracellular calcium activity, may reduce cognitive dysfunction caused by ECT.

METHOD

The lipid-soluble calcium channel-blocking drug nicardipine or matching placebo were randomly assigned to 26 patients with major depressive disorder receiving ECT. A rater blind to the experimental condition administered the Hamilton Depression Rating Scale, the Montgomery-Asberg Depression Rating Scale, the Beck Depression Inventory, the Mini-Mental State Examination and a comprehensive battery of neuropsychological tests prior to ECT, at the completion of ECT, and 6 months after ECT completion.

RESULTS

Compared with patients receiving placebo, patients taking nicardipine had significantly lower scores on the Hamilton and Montgomery-Asberg but not the Beck Depression rating scale scores at the completion of ECT. There were no differences between placebo and nicardipine groups in depression scores 6 months after ECT. Cognitive function declined over the course of ECT and improved over the next 6 months in both groups, but changes were statistically significant for only two subtests on the neuropsychological battery. Changes in Mini-Mental State Examination scores were small and were not significant at any point. There were no significant differences between nicardipine and placebo treated groups in any assessment of cognition.

DISCUSSION

Standard approaches to ECT in younger patients without preexisting neurological impairment do not produce cognitive side effects of sufficient severity for calcium channel-blocking agents to reduce these side effects demonstrably. Studies of treatments for cognitive impairment should be conducted in patients with risk factors for more severe cognitive impairment such as geriatric patients or patients with a history of interictal delirium during previous treatment with ECT. A possible effect of nicardipine in enhancing the antidepressant action of ECT requires further investigation in a study designed to test this action.

Lack of effect of 6 g inositol treatment of post-ECT cognitive function in humans

Cholinergic agonists have been reported to ameliorate ECT-induced memory impairment. Inositol metabolism is involved in the second messenger system for several muscarinic cholinergic receptors. Inositol 6 g daily was given in a cross-over double-blind manner for 5 days before the 5th or 6th ECT in a series of patients. No effect was found on post-ECT cognitive impairment.

NS-3, a TRH analog, reverses repeated ECS-induced deficits in water maze performance in the rat

Rats given five consecutive daily electroconvulsive shock (ECS) treatments and trained to run in the Morris water maze, starting three days posttreatment, showed deficits in learning and memory functions. Treatment before each training session with the thyrotropin-releasing hormone (TRH) analog NS-3 [(CG-3703), (3R),(6R)-6-methyl-5-oxo-3-thiomorphorinyl-l-histidyl-l-prolinamid e tetrahydrate] reversed these behavioral deficits. The possible use of TRH and its analogs as therapeutic treatment for the cognitive dysfunctions resulting from electroconvulsive shock treatment for depression and the possible involvement of central cholinergic systems in the cognitive dysfunctions are discussed.