Confusional States During Electroconvulsive Therapy for Late-Life Depression: A Prospective Cohort Study

Cognitive side effects, such as memory loss, associated with electroconvulsive therapy (ECT) have been extensively studied. However, knowledge about (sub)acute confusional states during ECT is limited, particularly in older adults with depression. Their incidence, recurrence, and co-occurrence remain unclear. This study aimed to describe the incidence, recurrence, co-occurrence, and clinical course of various subtypes of confusional states during ECT.

Data were derived from the 'Rivastigmine for ECT-induced Cognitive Adverse effects in Late-Life depression' (RECALL) prospective cohort study, involving 145 older adults (≥ 55 years) with a major depressive episode receiving ECT. We assessed different subtypes of confusional states: postictal and interictal delirium (PID and IID), postictal agitation (PIA), prolonged time to reorientation (TRO), and subacute general cognitive decline (Mini Mental State Examination decline ≥ 4 points) throughout the ECT course.

Over half of the older adults (55.9%) experienced at least one subtype of confusional state during their ECT course. The most prevalent subtypes were PIA (29.5%) and prolonged TRO (28.3%), while postictal (5.9%) and interictal delirium (4.2%) were less common. Recurrence rates varied, with interictal delirium (66.7%) and prolonged TRO (50.0%) showing the highest rates compared to postictal delirium (12.5%). Notably, 18.0% of older adults experienced more than one subtype of confusional state during their ECT course, and these states could emerge at any time during the ECT course.

This is the first study to comprehensively examine the clinical course of various subtypes of confusional states during ECT in older adults with depression Our findings reveal that confusional states are highly prevalent, heterogeneous, and may emerge at any time during the ECT course. Notably, since the instruments used were not designed to measure (subtypes of) confusional states during ECT, further research into the differentiation of (sub)acute confusional states is warranted.

EudraCT 2014-003385-24.