ECT Technique, Cognitive Effects, Schizophrenia-New Review

Out on PubMed, from Mustafa Cicek, a Turkish psychiatrist working in Switzerland, and colleagues, is this review:

 Is There Evidence That Stimulus Parameters and Electrode Placement Affect the Cognitive Side Effects of Electroconvulsive Therapy in Patients With Schizophrenia and Schizoaffective Disorder?: A Systematic Review.

Cicek M, McCall WV, Yao Z, Sackeim HA, Rosenquist P, Youssef NA.J ECT. 2020 Dec 22;Publish Ahead of Print. doi: 10.1097/YCT.0000000000000737. Online ahead of print.PMID: 33369995

The abstract is copied below:

Seventy percent of patients with treatment-resistant schizophrenia do not respond to clozapine. Electroconvulsive therapy (ECT) can potentially offer significant benefit in clozapine-resistant patients. However, cognitive side effects can occur with ECT and are a function of stimulus parameters and electrode placements. Thus, the objective of this article is to systematically review published clinical trials related to the effect of ECT stimulus parameters and electrode placements on cognitive side effects. We performed a systematic review of the literature up to July of 2020 for clinical studies published in English or German examining the effect of ECT stimulus parameters and/or electrode placement on cognitive side effects in patients with schizophrenia or schizoaffective disorder. The literature search generated 3 randomized, double-blind, clinical trials, 1 randomized, nonblinded trial, and 1 retrospective study. There are mixed findings regarding whether pulse width and stimulus dose impact on cognitive side effects. One study showed less cognitive side effect for right unilateral (RUL) than bitemporal (BT) electrode placement, and 2 studies showed a cognitive advantage for bifrontal (BF) compared with BT ECT. Only 1 retrospective study measured global cognition and showed post-ECT cognitive improvement with all treatment modalities using Montreal Cognitive Assessment in comparison to pre-ECT Montreal Cognitive Assessment scores. Current data are limited, but evolving. The evidence suggests that RUL or BF ECT have more favorable cognitive outcomes than BT ECT. Definitive larger clinical trials are needed to optimize parameter and electrode placement selection to minimize adverse cognitive effects.

The pdf is here.

And a table:

And from the text:

The modern literature on the effect of the EP and ECT parameters on cognition in patients with schizophrenia and schizoaffective disorder is limited to 5 studies. The results of these studies are difficult to synthesize as ECT technique differs among these studies. Three of these studies examined the effect of the EP on cognitive side effects of ECT.27,28,44 Two studies examined the
effect of manipulation of ECT parameters: pulse width25 and stimulus dose.26 One study examined the effect of EP as well as titration technique on cognitive side effects of ECT.28 The methods of cognitive assessment also varied among the studies. Included studies used some form of modern cognitive assessment, such as MMSI/HMSE, Weschler, COWA, and MoCA; however, there was substantial heterogeneity in the specific instruments used and the timing interval between treatment and testing.

This scholarly review is a very interesting and useful contribution to the ECT literature. It is striking to learn that a total n=390 makes up the entire (easily accessible) world's literature on the effects of stimulus parameters and electrode placement for patients with schizophrenia/schizoaffective disorder.

The results of these few studies are not surprising, as they track those of mood disorder populations.

Given that schizophrenia is the number one indication for ECT worldwide, and that millions of patients with this diagnosis have had ECT, it is remarkable that we still have such little certainty from large-scale clinical trials about optimized ECT technique.

There is no a priori reason to think that ECT tolerability would differ markedly by diagnosis, but, of course, this needs to be proven.

But the type of cognitive impairment at baseline may be different in schizophrenia than dementia, for example, and ECT's transient cognitive effects may not be in the same domains as the baseline problems in patients with schizophrenia. Some very psychotic patients may have "cognitive impairment" as a result of extreme disorganization, and ECT would quickly improve that. As is true for mood disorders, it is important not to sacrifice (antipsychotic) efficacy because of potentially exaggerated fears of cognitive impairment.

Dr. Cicek and colleagues are to be congratulated for their meticulous review of this important, and understudied, topic.