Keep calm and carry on: Maintaining self-control when intoxicated, upset, or depleted.

This study tested within-person associations between intoxication, negative affect, and self-control demands and two forms of self-control failure, interpersonal conflict, and neglecting responsibilities. Effortful control was hypothesised to act as a buffer, reducing individual susceptibility to these within-person effects. In contrast, reactivity was hypothesised to potentiate the within-person associations. 274 young adults aged 18-27 (56% women, 93% white) completed experience sampling assessments for up to 49 days over the course of 1.3 years. Results indicated independent within-person effects of intoxication, negative affect, and self-control demands on the outcomes. Hypothesised moderating effects of reactivity were not supported. Effortful control did not moderate the effects of self-control demands as expected. However, effortful control exhibited a protective effect when individuals were intoxicated or upset to reduce the likelihood of maladaptive behavioural outcomes.