ABSTRACT
Most of the scientific research on alcohol consumption behavior in humans is laboratory-based, as reflected by the ratio of laboratory vs. real-life contributions to this handbook. Studies in daily life, although having a long history in addiction research (Shiffman et al., Ann Behav Med 16:203-209, 1994), are in the minority. This is surprising, given that patients with substance use disorders are suffering in daily life and not in the laboratory setting. In other words, drinking patterns and symptoms of alcohol use disorder evolve not in the lab but in daily life, where patients show difficulties in limiting their alcohol intake accompanied with all kinds of related problems. The ultimate goal of all interventions, independent of being tailored toward restricted drinking or abstinence, is again an altered behavior in real life. Translated to practice, patients' behavior in the lab may not translate to daily life, often showing minimal ecological validity. Therefore, we have to question to which degree lab-based research findings translate into daily life. Fortunately, the current digital revolution provided us with more and more tools, enabling us to monitor, analyze, and change behavior in human everyday life. Our chapter does not intend to give a comprehensive overview of the daily life research on alcohol consumption over the last few decades as others do (Morgenstern et al., Alcohol Res Curr Rev 36:109, 2014; Piasecki, Alcohol Clin Exp Res 43:564-577, 2019; Shiffman, Psychol Asses 21:486-497, 2009; Votaw and Witkiewitz, Clin Psychol Sci 9:535-562, 2021; Wray et al., Alcohol Res Curr Rev 36:19-27, 2014). Instead, we aim at the following: first, to highlight the key advantages of ecological momentary assessment to motivate scientists to add daily life research components to their laboratory research and, second, to provide some guidance on how to begin with daily life research.
ABSTRACT
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.