Neural Effects of ECT in Patients With Schizophrenia: Systematic Review From Korea
Out on PubMed, from researchers in Korea, is this article:
Systematic Review of the Neural Effect of Electroconvulsive Therapy in Patients with Schizophrenia: Hippocampus and Insula as the Key Regions of Modulation.
Psychiatry Investig. 2021 Jun;18(6):486-499. doi: 10.30773/pi.2020.0438. Epub 2021 Jun 24.PMID: 34218638
The abstract is copied below:
Objective: Electroconvulsive therapy (ECT) has been the most potent treatment option for treatment-resistant schizophrenia (TRS). However, the underlying neural mechanisms of ECT in schizophrenia remain largely unclear. This paper examines studies that investigated structural and functional changes after ECT in patients with schizophrenia.
Methods: We carried out a systematic review with following terms: 'ECT', 'schizophrenia', and the terms of various neuroimaging modalities.
Results: Among the 325 records available from the initial search in May 2020, 17 studies were included. Cerebral blood flow in the frontal, temporal, and striatal structures was shown to be modulated (n=3), although the results were divergent. Magnetic resonance spectroscopy (MRS) studies suggested that the ratio of N-acetyl-aspartate/creatinine was increased in the left prefrontal cortex (PFC; n=2) and left thalamus (n=1). The hippocampus and insula (n=6, respectively) were the most common regions of structural/functional modulation, which also showed symptom associations. Functional connectivity of the default mode network (DMN; n=5), PFC (n=4), and thalamostriatal system (n=2) were also commonly modulated.
Conclusion: Despite proven effectiveness, there has been a dearth of studies investigating the neurobiological mechanisms underlying ECT. There is preliminary evidence of structural and functional modulation of the hippocampus and insula, functional changes in the DMN, PFC, and thalamostriatal system after ECT in patients with schizophrenia. We discuss the rationale and implications of these findings and the potential mechanism of action of ECT. More studies evaluating the mechanisms of ECT are needed, which could provide a unique window into what leads to treatment response in the otherwise refractory TRS population.
Keywords: Electroconvulsive therapy; Hippocampus; Insula.; Schizophrenia; Treatment-resistant schizophrenia.
The pd is here.
And from the text:
This systematic review presents preliminary evidence of hippocampal and insular modulation after ECT in patients with schizophrenia. This holds true for morphometry, FC, and symptom association measures. Other potential candidates include the DMN, PFC, and thalamostriatal system, as demonstrated by MRS and fMRI studies, and the amygdala, along with the hippocampus and insula, which were associated with symptom reductions. However, due to the small number of studies, replication is indispensable to generalize and elaborate our understanding of the neurobiological underpinnings of the ECT effect in schizophrenia patients. We believe that ECT provides a unique window to the understanding and management of treatment-resistance in patients with schizophrenia. However, the effect and mechanism of action of ECT are most likely to be complex and possibly mediated by various structural, functional, and metabolic alterations. Dysfunctional neurotrophic factors in schizophrenia could partially be remedied by ECT, but other factors, including neurotransmitter changes, synaptic remodeling, and restoration of altered FC in other largely distributed networks, may also play an important role. To disentangle the mystifying mechanisms of ECT, augmentation of functional approaches (functional MRI, MRS, electroencephalography) with morphometric results might prove useful in future study designs.
This turns out to be a very interesting paper-the authors try to tease out brain changes in schizophrenia with ECT, using different neuroimaging modalities (measuring blood flow, brain metabolites, structure and function with MRI). It focuses on findings in hippocampus and insula. The theoretical discussion is extensive and includes consideration of whether the changes induced by ECT might be disease-specific, i.e. that they might differ between depression and schizophrenia.
For anyone interested in either ECT for schizophrenia or the mechanism of action ECT, this paper will be required reading, ~25 minutes.
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