Associations of Menstrual Cycle and Progesterone-to-Estradiol Ratio With Alcohol Consumption in Alcohol Use Disorder: A Sex-Separated Multicenter Longitudinal Study.

OBJECTIVE: Alcohol use disorder (AUD) constitutes a critical public health issue and has sex-specific characteristics. Initial evidence suggests that progesterone and estradiol might reduce or increase alcohol intake, respectively. However, there is a need for a better understanding of how the menstrual cycle in females and the ratio of progesterone to estradiol in females and males influence alcohol use patterns in individuals with AUD. METHODS: In this sex-separated multicenter longitudinal study, the authors analyzed 12-month data on real-life alcohol use (from 21,460 smartphone entries), menstrual cycle, and serum progesterone-to-estradiol ratios (from 667 blood samples at four individual study visits) in 74 naturally cycling females and 278 males with AUD between 2020 and 2022, using generalized and general linear mixed modeling. RESULTS: Menstrual cycle phases were significantly associated with binge drinking and progesterone-to-estradiol ratio. During the late luteal phase, females showed a lower predicted binge drinking probability of 13% and a higher predicted marginal mean of progesterone-to-estradiol ratio of 95 compared with during the menstrual, follicular, and ovulatory phases (binge drinking probability and odds ratios vs. late luteal phase, respectively: 17%, odds ratio=1.340, 95% CI=1.031, 1.742; 19%, odds ratio=1.523, 95% CI=1.190, 1.949; and 20%, odds ratio=1.683, 95% CI=1.285, 2.206; difference in progesterone-to-estradiol ratios, respectively: -61, 95% CI=-105.492, -16.095; -78, 95% CI=-119.322, -37.039; and -71, 95% CI=-114.568, -27.534). In males, a higher progesterone-to-estradiol ratio was related to lower probabilities of binge drinking and of any alcohol use, with a 10-unit increase in the hormone ratio resulting in odds ratios of 0.918 (95% CI=0.843, 0.999) and 0.914 (95% CI=0.845, 0.988), respectively. CONCLUSIONS: These ecologically valid findings suggest that high progesterone-to-estradiol ratios can have a protective effect against problematic alcohol use in females and males with AUD, highlighting the progesterone-to-estradiol ratio as a promising treatment target. Moreover, the results indicate that females with AUD may benefit from menstrual cycle phase-tailored treatments.

ON-ICE trial: Investigation of the combined effects of oxytocin and naltrexone on stress-induced and alcohol cue-induced craving in alcohol use disorder-Study protocol of a phase II randomised double-blind placebo-controlled parallel-group trial.

INTRODUCTION: Although alcohol dependence (AD) is highly prevalent, only few medications are approved for its treatment. While currently approved medications, such as naltrexone (NTX), reduce craving and relapse risk to a certain extent, new approaches are needed to complement these pharmaca. One potential compound is oxytocin (OXY), which proved beneficial effects on alcohol craving and stress reactivity in preliminary clinical studies and synergism with NTX effects. METHODS AND ANALYSIS: This clinical phase II trial is a monocentre two-armed, placebo (PLC)-controlled, 1:1 randomised, double-blind, parallel-group study. 62 participants with AD will be randomised to receive either intranasal OXY spray (24 IU) or PLC spray plus oral NTX (50 mg) for 2 days, and alcohol craving will be assessed using a validated combined stress-exposure and cue-exposure experiments and MRI. The primary outcome will be the intensity of alcohol craving, assessed using the Alcohol Urge Questionnaire (AUQ), 60 min after OXY/PLC application, directly after the stress and cue exposures. Secondary outcomes include subjective stress, negative affect, cortisol and OXY plasma levels, and neural response to alcohol and emotional cues and natural rewards. Follow-up drinking data were collected over 90 days. The primary efficacy analysis will test the difference between the verum and the PLC group in the distribution of AUQ craving scores. Appropriate statistical analysis will be used for the evaluation of the secondary outcomes. ETHICS AND DISSEMINATION: This trial has been approved by the ethics committee of Heidelberg University and competent authority. All participants in the trial will provide written informed consent. The study will be conducted according to the principles of the Declaration of Helsinki and in accordance to the German Medicinal Products act. Results of this study will be disseminated in peer-reviewed scientific journals and deidentified data, and the statistical analysis plan will be made available via open-access online repositories. TRIAL REGISTRATION NUMBERS: EudraCT 2021-003610-40 and NCT05093296.