Cognitive Adverse Effects of Electroconvulsive Therapy: A Discrepancy Between Subjective and Objective Measures?

The myth of brain damage: no change of neurofilament light chain during transient cognitive side-effects of ECT

Electroconvulsive therapy (ECT) is an effective, safe, and mostly well-tolerated treatment for patients with severe or difficult to treat depression or psychotic disorders. However, a relevant number of patients experience subjective and/or objective cognitive side-effects. The mechanism of these transient deficits is not yet clear. Thus, our study prospectively investigated neurofilament light chain (NfL) concentrations as a highly sensitive biomarker for neuroaxonal damage along with cognitive performance during a course of ECT. Serum NfL concentrations from 15 patients with major depressive disorder receiving ECT were analyzed (1) 24 h before the first ECT, (2) 24 h and (3) 7 days after the last ECT (45 measurements in total). Neuropsychological testing including memory, executive functions and attention was performed at each time-point. NfL concentrations did not change between the three time-points, while a temporary cognitive impairment was found. Even in the subset of patients with the strongest impairment, NfL concentrations remained unchanged. Neuropsychological testing revealed the common pattern of transient cognitive side-effects with reduced performance 24 h post-ECT (global cognition score: p < 0.001; memory: p = 0.043; executive functions: p = 0.002) and return to baseline after 7 days (all p < 0.001). Our study adds to the evidence that neither ECT per se nor the transient cognitive side-effects seem to be associated with an increase of NfL as a marker of neuroaxonal damage. In contrast, we discuss cognitive side effects to be potentially interpreted as a byproduct of ECT's neuroplastic effects.

Unmasking patient diversity: Exploring cognitive and antidepressive effects of electroconvulsive therapy

BACKGROUND

Electroconvulsive therapy (ECT) is an established treatment for depression, but more data on effectiveness and safety in clinical practice is needed. The aim of this register-based study was to investigate short-term effectiveness and cognitive safety after ECT, evaluated by clinicians and patients. Secondary, we investigated predictors for remission and cognitive decline.

METHODS

The study included 392 patients from the Regional Register for Neurostimulation Treatment in Western Norway. Depressive symptoms and cognitive function were assessed with Montgomery-Åsberg Depression Rating Scale and Mini-Mental State Examination (clinician-rated) and Beck Depression Inventory and Everyday Memory Questionnaire (patient-rated). Assessments were done prior to ECT-series and a mean of 1.7 days after (range 6 days before and 12 days after) end of ECT-series. Paired samples t-tests were extended by detailed, clinically relevant subgroups. Predictors were examined using logistic regression.

RESULTS

Clinician- and patient-rated remission rates were 49.5 and 41.0%, respectively. There was a large reduction in depressive symptoms and a small improvement in cognition after ECT, but we also identified subgroups with non-response of ECT in combination with cognitive decline (4.6% clinician-rated, 15.7% patient-rated). Positive predictors for patient- and clinician-rated remission were increasing age, shorter duration of depressive episode, and psychotic features. Antipsychotic medication at the commencement of treatment and previous ECT-treatment gave higher odds of clinician-rated remission, whereas higher pretreatment subjective depression level was associated with lower odds for patient-rated remission. Clinician-rated cognitive decline was predicted by higher pretreatment MMSE scores, whereas psychotic features, increasing age, and greater pretreatment subjective memory concerns were associated with lower odds for patient-rated cognitive decline.

CONCLUSIONS

Our study supports ECT as an effective and safe treatment, although subgroups have a less favorable outcome. ECT should be considered at an early stage for older patients suffering from depression with psychotic features. Providing comprehensive and balanced information from clinicians and patients perspectives on effects and side effects, may assist in a joint consent process.

How electroconvulsive therapy works in the treatment of depression: is it the seizure, the electricity, or both?

We have known for nearly a century that triggering seizures can treat serious mental illness, but what we do not know is why. Electroconvulsive Therapy (ECT) works faster and better than conventional pharmacological interventions; however, those benefits come with a burden of side effects, most notably memory loss. Disentangling the mechanisms by which ECT exerts rapid therapeutic benefit from the mechanisms driving adverse effects could enable the development of the next generation of seizure therapies that lack the downside of ECT. The latest research suggests that this goal may be attainable because modifications of ECT technique have already yielded improvements in cognitive outcomes without sacrificing efficacy. These modifications involve changes in how the electricity is administered (both where in the brain, and how much), which in turn impacts the characteristics of the resulting seizure. What we do not completely understand is whether it is the changes in the applied electricity, or in the resulting seizure, or both, that are responsible for improved safety. Answering this question may be key to developing the next generation of seizure therapies that lack these adverse side effects, and ushering in novel interventions that are better, faster, and safer than ECT.

Trajectories of Efficacy and Cognitive Function During Electroconvulsive Therapy Course in Young Adults with Treatment-Resistant Depression

OBJECTIVE

Little is known about the effectiveness and cognitive side-effects of electroconvulsive therapy (ECT) in young adults with treatment-resistant depression (TRD). The primary aim of this prospective longitudinal observational trial was to examine the clinical features and cognitive outcomes of young adults with TRD undergoing ECT.

METHODS

Changes in depressive symptoms and objective and subjective cognitive function were assessed using repeated evaluation at baseline, after each ECT session, and at one-month follow-up using the Montgomery-Äsberg Depression Rating Scale (MADRS) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Forward Digital Span Test (FDST), and part of the Columbia Subjective Side Effects Schedule.

RESULTS

Of 41 inpatients, 35 (85.4%) and 12 (29.3%) met the criteria for response and remission after ECT, respectively. The greatest clinical improvements occurred during the first 3-4 ECT sessions. While 34 patients reported subjective cognitive impairment increased with ECT, immediate and delayed memory (RBANS) significantly increased after ECT, consistent with FDST results. Objective cognition significantly improved during follow-up, but subjective cognition remained impaired.

CONCLUSION

ECT is effective in young adults with TRD. Although subjective cognitive impairment increased during treatment, objective cognitive impairments were not observed.

Pharmacological interventions to diminish cognitive side effects of electroconvulsive therapy: A systematic review and meta-analysis

OBJECTIVE

The authors conducted a systematic review and meta-analysis of pharmacological interventions to diminish cognitive side effects of ECT.

METHODS

Electronic databases of Pubmed, PsycInfo, Embase and Scopus were searched from inception through 1 April, 2021, using terms for ECT (e.g. electroconvulsive therapy), cognitive outcome (e.g. cogni*) and pharmacological intervention (e.g. calcium channel blocker and general terms, like protein). Original studies with humans receiving ECT were included, which applied pharmacological interventions in comparison with placebo or no additive intervention to diminish cognitive side effects. Data quality was assessed using Risk of Bias and GRADE. Random-effects models were used. PROSPERO registration number was CRD42021212773.

RESULTS

Qualitative synthesis (systematic review) showed 52 studies reporting sixteen pharmacological intervention-types. Quantitative synthesis (meta-analysis) included 26 studies (1387 patients) describing twelve pharmacological intervention-types. Low-quality evidence of efficacy was established for memantine (large effect size) and liothyronine (medium effect size). Very low-quality evidence shows effect of acetylcholine inhibitors, piracetam and melatonin in some cognitive domains. Evidence of no efficacy was revealed for ketamine (very low-quality), herbal preparations with anti-inflammatory properties (very low to low-quality) and opioid receptor agonists (low-quality).

CONCLUSION

Memantine and liothyronine are promising for further research and future application. Quality of evidence was low because of differences in ECT techniques, study populations and cognitive measurements. These findings provide a guide for rational choices of potential pharmacological intervention research targets to decrease the burden of cognitive side effects of ECT. Future research should be more uniform in design and attempt to clarify pathophysiological mechanisms of cognitive side effects of ECT.