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OBJECTIVE: Electroconvulsive therapy (ECT) can be rapidly effective in treating severe depression. Right unilateral (RUL) or bitemporal (BT) electrode placement may affect the speed of ECT effectiveness although our current understanding of demographic and clinical factors for predicting predict speed of response and remission with ECT is limited. We investigated differences in improvement speed and also time to achieving response and remission criteria between brief-pulse moderate-dose (1.5 x seizure threshold) BT ECT and high-dose (6 x seizure threshold) RUL ECT. Additionally, we explored the influence of demographic and clinical characteristics.
METHODS: We analysed weekly 24-item Hamilton Depression Rating Scale scores obtained from severely depressed patients participating in the EFFECT-Dep trial (ISRCTN23577151). Improvement speeds in patients treated randomly with a course of either BT (n = 69) or RUL ECT (n = 69) were compared using independent sample t-tests. Weekly proportions of responders and remitters were compared using chi-square tests. Cox regression analyses were used to explore predictors of speed to achieve response and remission status.
RESULTS: We found no differences between RUL and BT ECT in speed of improvement or time to achieve response or remission. Exploratory analyses indicated that a wide variety of demographic and clinical features did not serve to predict speed of response and remission to ECT.
CONCLUSION: Electrode placement did not substantially influence speed of improvement, response and remission with twice-weekly brief-pulse ECT. Minimising the cognitive side-effects of ECT may be of more relevance when choosing between BT and RUL electrode placement for ECT.

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The discussion about whether or not to focus our attention on the ‘average’ ECT-treatment technique that suits the majority of our patients or tailor the treatment to the needs of individual patients is ongoing. The question is, however, whether the available evidence permits us to to offer treatment ‘à la tête du client’.

The start of a treatment course can be personalized by choosing electrodeplacement (EP) (e.g. bilateral in case of a severe or life-threatening condition, when fast improvement prevails over cognitive impact), parameter selection (e.g. a shorter pulse-width in order to avoid cognitive side-effects), and a dosing strategy. A fixed-dose will lead to overdosing in some patients (causing side-effects) and under-dosing in others (delaying/decreasing response) (1)

Adjusting an ongoing treatment-technique can be based on response, side-effects or on the quality of the elicited seizure (EEG). In case of inadequate response, the clinician can decide to switch EP or to increase dose. There is no consensus as to the number of sessions after which technique should be changed. In case of intolerable side-effects, parameter selection and/or EP can be adjusted. The evidence that is available to guide these steps is limited. There is some evidence for a relation between several EEG-characteristics and outcome. Thus, in the event of an inadequate seizure, changing the anesthetic regimen, optimizing ventilation, lengthening the anesthetic-ECT time-interval or increasing the stimulus dose, can be of help.

1. Sackeim et al. Treatment of the modal patient: does one size fit nearly all? J ECT 2001;17:219-222.

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We know from past meta-analyses that several clinical variables are associated with electroconvulsive therapy (ECT) outcome in major depression. In this lecture we give an update of clinical variables associated with ECT outcome and dig deeper into the fact that these variables also seem to be somehow associated with each other. We attempt to disentangle the interdependence between the clinical variables and try to distil the most important predictors of treatment success to help improve patient-treatment matching.

Therefore we created a conceptual framework of interdependence between predictors capturing age, episode duration, and treatment resistance, all variables associated with ECT outcome, and the clinical symptoms of what we have called ‘core depression’, i.e., depression with psychomotor agitation, retardation, or psychotic features, or a combination of the three.

We validated this model in a sample 73 patients using path analyses, with the size and direction of all direct and indirect paths being estimated using structural equation modelling. Results of these analyses were recently published and will also be disscussed at this symposium. The conceptual model could eb largely validated, the most important finding being that age was only indirectly associated with ECT outcome, meaning that age seems to be associated with ECT outcome only because more psychomotor and psychotic symptoms occur in elderly patients with a depressive disorder.

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Electroconvulsive brain stimulation may represent the strongest manipulation available to study brain plasticity in humans. Brain plasticity induced by electroconvulsive brain stimulation, profoundly improves disturbed emotion and motivation in patients with depression. Electroconvulsive therapy (ECT) is a highly effective and safe treatment for psychiatric disorders like severe depression. However, there is ongoing concern about the negative impact of ECT on brain function and cognition that is, surprisingly, only seen in a part of the treated patients. After 80 years of research on ECT, virtually nothing is known about the mechanisms underlying these strong individual differences in cognitive changes induced by ECT. A first step would be to better quantify the pattern and severity of the adverse cognitive outcomes in order to better distinguish patients that suffer from adverse cognitive outcomes from those that do not or even improve. By better distinguishing of these subgroups, a second step towards understanding can be taken: to identify the factors that predict adverse cognitive outcomes. Our research aims to advance understanding of the mechanisms of cognitive plasticity and reveal the pre-treatment profiles that render a patient cognitive vulnerable or resilient.