Andrea C. King

Background High‐resolution ecological momentary assessment (HR‐EMA) can assess acute alcohol responses during naturalistic heavy drinking episodes. The goal of this study was to use HR‐EMA to examine drinking behavior and subjective responses to alcohol in risky drinkers (moderate–severe alcohol use disorder [MS‐AUD], heavy social drinkers [HD]) and light drinkers (LD). We expected that risky drinkers would endorse greater alcohol stimulation and reward, with lower sedation, than LD, even when controlling for amount of alcohol consumed. Methods Participants ( N = 112; 54% male, M ± SD age = 27.2 ± 4.2 years) completed smartphone‐based HR‐EMA during one typical alcohol drinking occasion and one non‐alcohol‐drinking occasion in their natural environment. Participants were prompted to complete next‐day surveys that assessed drinking‐related outcomes, study acceptability, and safety. Results HR‐EMA prompt completion rates were excellent (92% and 89% for the alcohol and nonalcohol episodes, respectively). The MS‐AUD group consumed the most alcohol with the highest estimated blood alcohol concentration (eBAC) by the end of the alcohol drinking episode (0.14 g/dL) versus LD (0.02 g/dL), with HD intermediate (0.10 g/dL). Relative to LD, MS‐AUD and HD endorsed greater positive effects of alcohol (stimulation, liking, and wanting). Conclusions This study is the first to use HR‐EMA to measure and compare real‐world acute alcohol responses across diverse drinker subgroups, including persons with MS‐AUD. Results demonstrate that risky drinkers experience heightened pleasurable effects measured in real‐time during natural‐environment alcohol responses. Rather than drinking excessively to eventually achieve desirable subjective effects, risky drinkers show sensitivity to positive alcohol effects throughout a heavy drinking episode.