Considerable research has documented the optimization utility of stimulants in sleep deprived Soldiers and aviators, however, the research for enhancement purposes has demonstrated mixed results. One significant factor that may influence enhancement properties is general intelligence such that low performers exhibit stronger enhancement effects than high performers. The objective of this study is to determine whether stimulants (specifically, modafinil and Adderall) can enhance Soldier cognitive abilities and performance on military tasks. To do so, a within-subjects design will be employed using healthy, rested Soldiers and measuring performance on a set of basic cognitive assessments and operationally relevant tasks.

Inclusion Criteria:

• Must be at least 18 years old.
• Must have normal hearing, vision or corrected to normal vision, and cognitive function as determined by self-report
• Must have obtained at minimum 6 hours of sleep prior to all testing sessions, as assessed by actigraphy data and self-report. Should the actiwatch malfunction, reliance on self-report will suffice. If the subject does not meet this requirement, he will be asked to reschedule
• Must have refrained from consumption of stimulants (including caffeine) and over the counter medications which may induce drowsiness for a minimum of 16 hours prior to each test session, and nicotine, 8 hours, prior to all testing sessions, assessed by self-report.

Exclusion Criteria:

• Currently taking medications which induce drowsiness, such as over-the-counter antihistamines. Any self-medication will be assessed through self-report.
• No current medical conditions or medications affecting cognitive function or attention as determined by screening by study physician or medical practitioner
• Current or recent use (as determined by study physician or medical practitioner) of medications that may interact with the test articles. Determined by self-report and exclusion at the discretion of the study physician or medical practitioner.
• Any history of any attention deficit condition requiring medication. A history of any attention deficit condition with medication is disqualifying as the potential interactions with testing are unknown and would therefore produce a potential source of confounding or bias into the results of the study.
• Any history of psychological/psychiatric disorder.
• Any history of addiction or substance abuse as assessed through self-report.
• Any history of metabolic disorder such as dysthyriodism.
• Any history of significant cardiovascular disease or hypertension.
• Any history of hepatic or renal disorder.
• Females will be excluded given that the drugs administered could potentially negatively impact the very early stages of pregnancy.
• Any ingestion of substances that may interact with the test articles or potentially skew the results within the last 16 hours prior to testing including over-the-counter medications, supplements, etc. (see attached list to be reviewed with subject).