Targeting Slow Wave Sleep Deficiency in Late-Life Depression: A Case Series With Propofol

Repurposing General Anesthetic Drugs to Treat Depression: A New Frontier for Anesthesiologists in Neuropsychiatric Care

During the last 100 years, the role of anesthesiologists in psychiatry has focused primarily on facilitating electroconvulsive therapy and mitigating postoperative delirium and other perioperative neurocognitive disorders. The discovery of the rapid and sustained antidepressant properties of ketamine, and early results suggesting that other general anesthetic drugs (including nitrous oxide, propofol, and isoflurane) have antidepressant properties, has positioned anesthesiologists at a new frontier in the treatment of neuropsychiatric disorders. Moreover, shared interest in understanding the biologic underpinnings of anesthetic drugs as psychotropic agents is eroding traditional academic boundaries between anesthesiology and psychiatry. This article presents a brief overview of anesthetic drugs as novel antidepressants and identifies promising future candidates for the treatment of depression. The authors issue a call to action and outline strategies to foster collaborations between anesthesiologists and psychiatrists as they work toward the common goals of repurposing anesthetic drugs as antidepressants and addressing mood disorders in surgical patients.

Daytime dexmedetomidine sedation with closed-loop acoustic stimulation alters slow wave sleep homeostasis in healthy adults

Background

The alpha-2 adrenergic agonist dexmedetomidine induces EEG patterns resembling those of non-rapid eye movement (NREM) sleep. Fulfilment of slow wave sleep (SWS) homeostatic needs would address the assumption that dexmedetomidine induces functional biomimetic sleep states.

Methods

In-home sleep EEG recordings were obtained from 13 healthy participants before and after dexmedetomidine sedation. Dexmedetomidine target-controlled infusions and closed-loop acoustic stimulation were implemented to induce and enhance EEG slow waves, respectively. EEG recordings during sedation and sleep were staged using modified American Academy of Sleep Medicine criteria. Slow wave activity (EEG power from 0.5 to 4 Hz) was computed for NREM stage 2 (N2) and NREM stage 3 (N3/SWS) epochs, with the aggregate partitioned into quintiles by time. The first slow wave activity quintile served as a surrogate for slow wave pressure, and the difference between the first and fifth quintiles as a measure of slow wave pressure dissipation.

Results

Compared with pre-sedation sleep, post-sedation sleep showed reduced N3 duration (mean difference of -17.1 min, 95% confidence interval -30.0 to -8.2, P=0.015). Dissipation of slow wave pressure was reduced (P=0.02). Changes in combined durations of N2 and N3 between pre- and post-sedation sleep correlated with total dexmedetomidine dose, (r=-0.61, P=0.03).

Conclusions

Daytime dexmedetomidine sedation and closed-loop acoustic stimulation targeting EEG slow waves reduced N3/SWS duration and measures of slow wave pressure dissipation on the post-sedation night in healthy young adults. Thus, the paired intervention induces sleep-like states that fulfil certain homeostatic NREM sleep needs in healthy young adults.

Clinical trial registration

ClinicalTrials.gov NCT04206059.

Propofol enhancement of slow wave sleep to target the nexus of geriatric depression and cognitive dysfunction: protocol for a phase I open label trial

INTRODUCTION

Late-life treatment-resistant depression (LL-TRD) is common and increases risk for accelerated ageing and cognitive decline. Impaired sleep is common in LL-TRD and is a risk factor for cognitive decline. Slow wave sleep (SWS) has been implicated in key processes including synaptic plasticity and memory. A deficiency in SWS may be a core component of depression pathophysiology. The anaesthetic propofol can induce electroencephalographic (EEG) slow waves that resemble SWS. Propofol may enhance SWS and oral antidepressant therapy, but relationships are unclear. We hypothesise that propofol infusions will enhance SWS and improve depression in older adults with LL-TRD. This hypothesis has been supported by a recent small case series.

METHODS AND ANALYSIS

SWIPED (Slow Wave Induction by Propofol to Eliminate Depression) phase I is an ongoing open-label, single-arm trial that assesses the safety and feasibility of using propofol to enhance SWS in older adults with LL-TRD. The study is enrolling 15 English-speaking adults over age 60 with LL-TRD. Participants will receive two propofol infusions 2-6 days apart. Propofol infusions are individually titrated to maximise the expression of EEG slow waves. Preinfusion and postinfusion sleep architecture are evaluated through at-home overnight EEG recordings acquired using a wireless headband equipped with dry electrodes. Sleep EEG recordings are scored manually. Key EEG measures include sleep slow wave activity, SWS duration and delta sleep ratio. Longitudinal changes in depression, suicidality and anhedonia are assessed. Assessments are performed prior to the first infusion and up to 10 weeks after the second infusion. Cognitive ability is assessed at enrolment and approximately 3 weeks after the second infusion.

ETHICS AND DISSEMINATION

The study was approved by the Washington University Human Research Protection Office. Recruitment began in November 2022. Dissemination plans include presentations at scientific conferences, peer-reviewed publications and mass media. Positive results will lead to a larger phase II randomised placebo-controlled trial.

TRIAL REGISTRATION NUMBER

NCT04680910.

Hypersomnia as a predictor of response to intravenous ketamine/intranasal esketamine in treatment resistant depression

BACKGROUND

Sleep disturbances are highly prevalent in depressive episodes and are linked to higher mood severity and suicidal behaviors. Slow wave sleep (SWS) and REM sleep are compromised in depression. Current evidence suggests that rapid antidepressant effects of intravenous (IV) ketamine in patients with treatment-resistant depression (TRD) is mediated by its effects on SWS and REM sleep. Sleep phenotypes may help predict ketamine response.

METHOD

In this observational study, we investigated differences in rates of response among sleep phenotypes defined by QIDS-SR in a cohort of patients with TRD (n = 52) treated with IV ketamine or intranasal (IN) esketamine. Also, we explored a neurovegetative symptoms of atypical depression (NVSAD) phenotype and its association between response and change in QIDS-SR following the treatment with IV ketamine/IN esketamine.

RESULTS

94 % of patients reported sleep difficulties and 62 % reported more than one sleep phenotype with middle and early insomnia being the most prevalent. Individuals with baseline hypersomnia showed higher response rates and more pronounced improvements on their QIDS-SR score. Additionally, 15 % of patients presented with NVSAD phenotype; the majority of whom achieved response and had higher reductions on QIDS-SR. A trend towards faster response was identified for hypersomnia and atypical depression phenotypes.

LIMITATIONS

Observational study design and lack of a placebo group.

CONCLUSIONS

Our data indicate that patients with TRD who have baseline hypersomnia and atypical depression features experienced a more substantial reduction in depressive symptoms and are more likely to achieve response with ketamine/esketamine. This could serve as a future predictor for clinical response.