Effects of dextroamphetamine, caffeine and modafinil on psychomotor vigilance test performance after 44 h of continuous wakefulness

Abstract

Summary Prolonged sleep loss impairs alertness, vigilance and some higher‐order cognitive and affective capacities. Some deficits can be temporarily reversed by stimulant medications including caffeine, dextroamphetamine, and modafinil. To date, only one study has directly compared the effectiveness of these three compounds and specified the doses at which all were equally effective in restoring alertness and vigilance following 64 h of wakefulness. The present study compared the effectiveness of these same three stimulants/doses following a less extreme period of sleep loss (i.e., 44 h). Fifty‐three healthy adults received a single dose of modafinil 400 mg (n = 11), dextroamphetamine 20 mg (n = 16), caffeine 600 mg (n = 12), or placebo (n = 14) after 44 h of continuous wakefulness. After 61 h of being awake, participants obtained 12 h of recovery sleep. Psychomotor vigilance was assessed bi‐hourly during waking and following recovery sleep. Relative to placebo, all three stimulants were equally effective in restoring psychomotor vigilance test speed and reducing lapses, although the duration of action was shortest for caffeine and longest for dextroamphetamine. At these doses, caffeine was associated with the highest percentage of subjectively reported side‐effects while modafinil did not differ significantly from placebo. Subsequent recovery sleep was adversely affected in the dextroamphetamine group, but none of the stimulants had deleterious effects on postrecovery performance. Decisions regarding stimulant selection should be made with consideration of how factors such as duration of action, potential side‐effects, and subsequent disruption of recovery sleep may interact with the demands of a particular operational environment.

A Unified Model of Performance for Predicting the Effects of Sleep and Caffeine

“…However, it may be possible that similarly representing U as a monotonic function of sleep debt could simultaneously account for the increased impairments during higher sleep debts and decreased impairments during lower sleep debts, thereby better (Table 1) in study V6. 17 Thin dotted vertical line denotes caffeine intake (d1 = 600 mg). Other descriptors are identical to those in Figure 1.…”

“…17 The TSD phase was preceded by one night of 8 h TIB (baseline) and followed by one night of 12 h TIB (recovery). All subjects performed a 5-min PVT every 2 h throughout their time awake.…”

Caffeine and energy drink use by combat arms soldiers in Afghanistan as a countermeasure for sleep loss and high operational demands

“…10,37 Higher daily caffeine intake of soldiers in combat units (J-MHAT 8) was also associated with disrupted sleep following night operations, which is consistent with the effect of caffeine on recovery sleep following its use to maintain cognitive function during an overnight period of sustained wakefulness. 19,20,38,39 Clearly, obtaining sufficient sleep would be the preferred option but if this is not possible, due to the demands of combat, then use of caffeine to counter the effects of sleep loss is one strategy consistently documented by studies conducted in various military training scenarios. 11,[15][16][17]36 An alternative explanation, suggested by Toblin et al, 25 is greater caffeine intake impacts the quality of sleep, thereby increasing daytime sleepiness and subsequent accidents.…”

Sustaining Executive Functions During Sleep Deprivation: A Comparison of Caffeine, Dextroamphetamine, and Modafinil

“…Participants were allowed to sleep at 20:00 Saturday evening (Day 3) until 08:00 the placebo group (P < 0.01). Interestingly, there was no significant difference among the groups with regard to the average pick-up time for each ring, F (3,38) = 0.93, P = 0.963, suggesting that these effects were not due simply to faster processing or motor speed. When the TOH was re-administered following a full night of recovery sleep, no drug group differences were apparent for total moves or for average pick-up times.…”

“…The total number of moves and pick-up times were averaged across the 4 trials for each subject. There was a significant main effect of drug group on the average number of moves to solve the puzzle across the 4 trials, F (3,38) = 3.20, P = 0.034 (see Figure 2). Tukey post hoc comparisons showed that the caffeine group solved the TOH 5-ring task with significantly (P < 0.01) fewer moves than either the placebo, dextroamphetamine, or modafinil groups (Figure 3).…”