The effects of depressed mood and 0.05 % blood alcohol concentration on risky driving in males

Males are more likely than females to use alcohol as a maladaptive coping mechanism to alleviate symptoms of depressed mood. The effects of a combination of subclinical depressed mood and doses of alcohol below the per se legal threshold of 0.08 % blood alcohol concentration (BAC) on risky driving are unclear, however. This manuscript presents a quasi-experimental, between-subjects study testing the influence of combined subclinical depressed mood and 0.05 % BAC on risky driving in a simulator and the mediation of decision-making. Following assessment of depressed mood (Beck Depression Inventory-II), a double-blinded protocol was used to randomise participants and administer either an alcohol (0.05 % BAC) or a placebo (0.00 % BAC) beverage. The Iowa Gambling Task tested decision-making and participants indicated whether they would decide to drive in the simulator. Driving simulation measured risky driving in real-time. Participants were healthy male drivers (n = 57; age M = 38.2, SD = 7.5). Using ANOVA, there were non-significant group differences in risky driving. Logistic regression revealed non-significant effects between groups in predicting the decision to drive. Mediation regression was used to explore the underlying mechanisms of decision-making on the prediction of risky driving under depressed mood. However, decision-making under risk was only identified as a significant predictor of mean merge acceleration on the highway. In addition to the limited sample size, outcomes were likely impacted by the mediation of emotion regulation. As this research area remains promising, recommendations are highlighted. One of them includes the use of a measure of depressed mood that is more sensitive to externalising behavioural symptoms in males.