Sustained Mood Improvement with Laughing Gas Exposure (SMILE): Study protocol for a randomized placebo-controlled pilot trial of nitrous oxide for treatment-resistant depression

by Karim S. Ladha, Jiwon Lee, Gabriella F. Mattina, Janneth Pazmino-Canizares, Duminda N. Wijeysundera, Fatemeh Gholamali Nezhad, Kaylyssa Philip, Vanessa K. Tassone, Fathima Adamsahib, Venkat Bhat, on behalf of the SMILE Study Investigators

Nitrous oxide has shown potentially as an efficacious intervention for treatment-resistant depression, yet there remains insufficient evidence pertaining to repeated administration of nitrous oxide over time and active placebo-controlled studies with optimal blinding. Thus, we aim to examine the feasibility and preliminary efficacy of a six-week follow up study examining the effects of a 4 week course of weekly administered nitrous oxide as compared to the active placebo, midazolam.

In this randomized, active placebo-controlled, pilot trial, 40 participants with treatment-resistant depression will receive either inhaled nitrous oxide (1 hour at 50% concentration) plus intravenous saline (100mL) or inhaled oxygen (1 hour at 50% concentration) plus intravenous midazolam (0.02 mg/kg in 100mL, up to 2mg) once per week, for 4 consecutive weeks. Participants will be followed up for 6 weeks starting from the first treatment visit. Primary feasibility outcomes include recruitment rate, withdrawal rate, adherence, missing data, and adverse events. The primary exploratory clinical outcome is change in Montgomery-Åsberg Depression Rating Scale (MADRS) score at day 42 of the study. Other exploratory clinical outcomes include remission (defined as MADRS score Discussion

This pilot study will provide valuable information regarding the feasibility and preliminary efficacy of repeated nitrous oxide administration over time for treatment-resistant depression. If feasible, this study will inform the design of a future definitive trial of nitrous oxide as an efficacious and fast-acting treatment for treatment-resistant depression.

ClinicalTrials.gov NCT04957368. Registered on July 12, 2021.

Comprehensive lifestyle modification interventions for metabolic syndrome: A systematic review and meta‐analysis

Abstract

Introduction

Previous systematic reviews and meta-analyses have mainly focused on improvements in the number of metabolic syndrome risk factors and individual changes in each risk factor, making it challenging to examine the impact of comprehensive lifestyle modification interventions on adherence to recommended health behaviors. To address this gap, we conducted a systematic and meta-analysis aimed at identifying clinical parameter levels associated with lifestyle modification outcomes and adherence to recommended health behaviors for individuals with metabolic syndrome.

Methods

A total of seven studies retrieved from four databases (CINAHL, Medline via PubMed, American Psychological Association PsycINFO, and Embase) were included in the review. The selected studies, which demonstrated improvements in health behaviors, all included diet and exercise as main factors of comprehensive lifestyle modification in home settings.

Results

Our findings suggest that a 6-month comprehensive intervention including diet and exercise can be effective in decreasing glucose levels and systolic blood pressure. However, given the limited available data, further studies investigating the efficacy of interventions of varying durations are needed.

Discussion

Although our review included a small number of studies, comprehensive lifestyle modifications consisting of at least two components (primarily diet and exercise) can improve health behaviors and some clinical parameters among individuals with metabolic syndrome. Future studies are needed to investigate the long-term effects of lifestyle modifications on health behavior adherence and explore effective interventions to address certain clinical parameters, such as high-density lipoprotein levels. Also, we recommend using objective and quantifiable measure to compare adherence to recommended lifestyle modifications across studies.

Clinical Relevance

This research provides empirical evidence of the effectiveness of comprehensive lifestyle modification and emphasizes the need to develop long-term nursing strategies in public health that can be used to effectively manage metabolic syndrome.