The effects of smokeless tobacco on performance and psychophysiological response.

The effects of smokeless tobacco (ST) on psychophysiological response and performance were examined in two studies. Study 1 compared heavy and moderate ST users on psychomotor tasks (simple reaction time/anticipation time and choice reaction time/movement time) in ST (2 g amount) and no smokeless tobacco (NST) conditions. Moderate users performed significantly better than heavy users; there were no significant psychomotor performance differences comparing ST/NST conditions. Heart rate and blood pressure were elevated equally for both groups with the use of ST. Heavy users reported significantly less state anxiety in both ST and NST conditions than moderate users. Study 2 replicated the psychomotor performance results of study 1 when comparing nonusers and ST users who were given four dose amounts of ST (NST, 1/3 mean dose, mean dose, and 5/3 mean) over 4 d. For the math and Stroop tasks, ST use resulted in 12.1% and 10.4% better performance than the NST condition. Physiological measures showed significant elevations during the ST conditions. No differences between dose amounts of ST were apparent for any of the measures. These studies demonstrate that ST users perform better than nonusers when having to react to cognitively challenging task situations.