Do smooth waters run deep? Alcohol intoxication and the effects of water consumption on driving-related cognitions and behavior.

The present study tested the effect of the combined use of alcohol and water on driving-related cognitions and behavior. Seventy-four female students performed a driving simulator task after having consumed alcohol or a placebo. Additionally, half of the participants consumed 0.5 liter of water. It was hypothesized that combining alcohol and water could lead to an underestimated perceived intoxication level resulting in more favorable driving cognitions and increased risk behavior. Our findings showed that the combined use of water and alcohol did not affect cognitions or behavior. Surprisingly, in the placebo condition, water intake increased risky driving cognitions and behavior in women with a history of accident involvement. Lacking a clear counterproductive effect when combined with alcohol, water could be a useful tool in limiting alcohol use among female drinkers.