“Conclusion seems to be - definitely works, but may have little use with individuals already performing at their peak or already on the high IQ range. Cognitive enhancement effects are mild. It would seem to be better to use eugeroics to "compensate" an underperforming brain.
Mechanisms of modafinil: A review of current research
The tendency of modafinil to increase alpha power and decrease theta power (Caldwell et al 2000; Chapotot et al 2003; Saletu et al 2004, 2005) in human subjects is both consistent with modafinil’s stimulant properties and suggestive that modafinil improves brain function, an effect shown in the helicopter pilot study (Caldwell et al 2000) and in the cognitive performance studies discussed below.
None of the studies regarding EEG changes from modafinil that we found measured modafinil’s effects on event-related EEG changes in instances of mental exertion, but modafinil’s resting EEG profile and stimulant properties do suggest that it would enhance mental performance, at least in individuals in the condition of sleep-deprivation, a common factor in stimulant abusers. A number of studies testing modafinil’s effects on neurocognitive functioning tend to confirm that modafinil mildly enhances cognitive performance in healthy volunteers, especially with regards to executive function. These results are summarized in Tables 1–3. There were two studies published by Randall et al that showed little or no significant effect of modafinil on neurocognitive test performance in healthy individuals (Randall et al 2003, 2004), but a later review done by this group on their own research showed that modafinil did improve neurocognitive performance in average IQ subjects but not high IQ subjects (Randall et al 2005). The authors concluded that this indicates that modafinil has limited cognitive enhancing effects in already high-performing well-rested individuals, but they did not consider ceiling effects in neurocognitive tests designed to measure cognitive impairment as some of the other studies did (Turner et al 2003; Muller et al 2004).