Sleep DeprivationPhase 4NCT07830056
Modafinil to Optimize the Performance of Cold-Stressed Sleep-Deprived Personnel
A Phase 4 study testing Modafinil (M) and 200 mg Microcrystalline Cellulose in people with Sleep Deprivation and Cold Exposure, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
Trial summary
Environmental and workplace stressors are common and often unavoidable in military operations. Two critical stressors are cold stress and sleep loss. They both can substantially degrade operational effectiveness. Read more about this study
- Who is it for?
- Ages 17 to 39 yearsHealthy volunteers can take part
- Conditions the study is for
- Sleep Deprivation, Cold Exposure
- What is being tested?
- Modafinil (M) and 200 mg Microcrystalline Cellulose
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 33 participants
- Where
- 1 siteUnited States
- Study dates
- 18 Feb 2025to Dec 2026
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 17 to 39 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- Healthy, men and women aged 18-39 years old. Active-duty military personnel who are 17 years of age will also be allowed to participate.
- Willing to refrain from the use of caffeine - including dietary supplements that contain caffeine - alcohol, and nicotine 24 hours prior to data collection.
- Willing to refrain from vigorous physical activity 24 hours prior to data collection.
- Willing to refrain from any dietary supplement use within one week of initial screening and at any time while enrolled in the study (except a multi-vitamin containing up to 100% RDA).
- Willing to consume study diets throughout the course of the study.
- Supervisory approval for participation if permanent party military or a federal employee.
Who cannot join
- Use of modafinil or armodafinil in the last 3 months.
- Known allergy to modafinil or armomodafinil.
- Current medical profile, or condition, that limits, compromises, or is likely to render inconsistent performance with Grip Strength, Finger Tapping, or cardiovascular exercise on an exercise bike.
- a. Individuals taking substances that directly interact with modafinil, alertness/attention/concentration, or sympathetic tone: stimulants; decongestants, barbiturates, bronchodilators; SNRIs; opioids; appetite suppressants; anti-obesity medications; b. Individuals taking substances which inhibit CYP3A4 (penicillins; macrolide antibiotics; fluoroquinolones; lomitapide; goldenseal) or MAO inhibitors.
- Individuals taking substances which induce CYP3A4 (carbamazepine, phenobarbital, rifampin) to a greater than minimal degree: systemic steroids; anti-gout agents (Exceptions can be recommended to PI for CYP3A4 inducers which do not fall into other listed categories).
- Individuals taking substances which are metabolized by CYP450 enzymes 1A2, 2B6, 2C19, or 3A4: immune-suppressant/-modulatory drugs; SSRIs; TCAs; anti-coagulants; antituberculosis agents; antimalarials; antineoplastic agents; antibody-derived drugs; antivirals; azole antifungals; anti-parasitic agents; abortive migraine medications; muscle relaxants; sex hormones or modulators; ibrexafungerp; lefamulin; palovarotene; propranolol.
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- Females who are pregnant or breastfeeding, have a positive- pregnancy test, or plan on becoming pregnant in the next 3 months.
- Individuals currently taking/using contraceptives (i.e., oral contraceptive pill, intrauterine device, contraceptive implant, contraceptive injection, etc.) other than condoms.
- Current or history of mental health issues, illness, or condition (i.e., attention deficit hyperactivity disorder, autism spectrum disorder, diagnosed depression or anxiety disorders) that OMSO physician/healthcare provider believes puts the volunteers at increased risk.
- Current or history of psychosis, or history of suicidal or homicidal ideations within the past 2 years.
- History of cold injuries or cold-induced asthma.
- Raynaud's syndrome.
- Previous hand/finger injuries that impair dexterity and hand function.
- Metal hardware (plates/screws) in the upper extremities (arm/hands).
- Abnormal blood count (For example: hemoglobin (Hb) outside of the typical normal values reported by LabCorp in accordance with OMSO (Normal [Hb] Males = 12.6-17.7 g/dL; Females = 11.1-15.9 g/dL) or hematocrit (Hct) outside of the normal ranges (Normal Hct Males = 37.5-51.0%; Females = 34.0-46.6%) levels, presence of abnormal blood laboratory measures (e.g., hemoglobin S or sickle cell traits).
- Current or history of alcohol abuse (defined as Harmful Use by the World Health Organization), those who meet criteria for alcohol abuse disorder (as outlined in the DSM-5), or other substance abuse (i.e., the use of illegal drugs or the use of prescription or over-the-counter drugs for purposes other than those for which they are meant to be used, or in excessive amounts).
- Diagnosed sleep disorders (i.e., sleep-apnea, narcolepsy, etc.).
- Diseases and disorders of the metabolic, cardiovascular, endocrine, neurological, or gastrointestinal systems that in determination of OMSO are expected to interfere with safe conduct of the study.
- A medical diagnosis of high blood pressure (hypertension).
- Heart problems or prior heart attack.
- Regular daily use of medication that may significantly interfere with the study drug or outcomes, as determined by the OMSO physician/healthcare provider.
- Known allergies to medical adhesives.
- Difficulty swallowing large pills (self-reported) for those individuals unwilling to utilize the rectal suppository of the telemetric pill.
- History of obstructive disease of the gastrointestinal tract including (but not limited to) diverticulosis, diverticulitis and inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis, or previous gastrointestinal surgery, etc. that OMSO physician/healthcare provider believes puts the volunteers at increased risk.
- Donated blood within 8 weeks prior to study participation.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
US Army Research Institute of Environmental Medicine
Natick, Massachusetts, 01760
Harris R Lieberman, PhD, 508-206-2326, harris.r.lieberman.civ@health.mil
Danielle M Arcidiacono, MS, 508-206-2404, danielle.m.arcidiacono.civ@health.mil
About this study
Environmental and workplace stressors are common and often unavoidable in military operations. Two critical stressors are cold stress and sleep loss. They both can substantially degrade operational effectiveness. Various countermeasures are available to mitigate the adverse effects of these stressors, but due to operational requirements many are of limited use in the field. Modafinil is a drug that mitigates the effects of sleep deprivation and potentially cold stress, and modafinil may prevent performance degradation due to the combination of these stressors. This study will help determine if modafinil alters body-heat production and prevents cognitive and physical performance degradation due to cold stress in rested and sleep-deprived volunteers.
- Conditions
- Sleep Deprivation, Cold Exposure
- Being tested
- Modafinil (M), 200 mg Microcrystalline Cellulose
- Keywords
- Modafinil, sleep deprivation, cold stress
- Medical subject headings
- Sleep Deprivation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Modafinil (M)Drug
Evaluating the effect of Modafinil under both sleep deprivation and acute cold exposure on thermoregulation, cognitive flexibility/performance, and dexterity.
200 mg Microcrystalline CelluloseDrug
Placebo intervention to compare to modafinil intervention.
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | 200 mg Microcrystalline Cellulose Receives: Drug: 200 mg Microcrystalline Cellulose |
| Modafinil | Active comparator | 200 mg Modafinil Receives: Drug: Modafinil (M) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Height (in)
Height will be measured in inches using a stadiometer.
Measured: Familiarization 1 (Day -2)
Body Weight (kg)
Body weight will be measured in kilograms using a calibrated electronic scale.
Measured: Familiarization 1 (Day -2)
Body Composition: DXA Fat Mass (lbs)
Fat mass will be measured in kilograms via dual x-ray absorptiometry and used to calculate body fat percentage (fat mass/body weight).
Measured: Familiarization 1 (Day -2)
Body Composition: DXA Lean Mass (lbs)
Lean mass will be measured in pounds using dual x-ray absorptiometry.
Measured: Familiarization 1 (Day -2)
Body Composition: DXA Bone Mineral Content (lbs)
Bone mineral content (BMC) will be measured in pounds using dual x-ray absorptiometry.
Measured: Familiarization 1 (Day -2)
Sleep & Physical Activity
Physical activity and sleep duration will be recorded in minutes per day with a wrist actigraphy monitoring system (Actiwatch Spectrum Plus, Koninklijke Philips N.V., Amsterdam, NL or equivalent device). The accelerometer will be placed on the volunteer's wrist on the first familiarization day, worn continuously throughout the entirety of study participation (11 days total), and returned after a 2-day washout period after the second overnight collection. Activity and sleep measurements recorded by the accelerometer will be utilized to determine sleep/wake times of volunteers throughout the study duration.
Measured: Familiarization 1 to Study Completion (11 Days)
Cold Exposure: Core Temperature
Core temperature will be measured continuously at baseline (room temperature) and during cold exposure using a telemetric thermometer capsule (e-Celsius® Performance Capsule, BodyCap, Saint-Clair, France, or similar). Volunteers will either insert the capsule as a rectal suppository the morning of testing, or opt to ingest orally the night (at least 12 hours) prior to data collection to ensure deep core body temperature is accurately monitored. Volunteers will be removed from testing if core temperature decreases to 35 degrees Celcius or lower.
Measured: Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cold Exposure: Skin Temperature
Skin temperature will be continuously measured in Celcius at baseline (room temperature) and during cold exposure using Thermochron iButtons attached at the volunteer's chest, triceps, hand, thigh, calf, and foot.
Measured: Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Dexterity: Finger Tapping Task (FTT)
The FTT is an approximately 10 minute test used to assess manual dexterity and visuomotor coordination. Volunteers are asked to follow simply motor commands using their hands and fingers while seated using a standard 8-finger QWERTY keyboard position (left fingers resting on ASDF, right fingers resting on JKL;). Volunteers are presented varying finger tap sequences on a computer displaying spatially compatible keys matching the standard position (ASDFJKL;) and asked to press the corresponding key while wearing Army issued contact gloves. The presentation time of cues will be adjusted throughout the task at variable difficulties to assess visuomotor response thresholds. Volunteers are scored based on how quickly finger taps are correctly executed in the presented sequence without errors of omission, commission, or excursions.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cognitive Assessment: Scanning Visual Vigilance
Volunteers will continuously scan a computer screen to detect stimuli that are present in irregular intervals approximately every 1 minute. Volunteers will be scored based on whether a stimulus is correctly detected (max score of 30), falsely detected, and the response time in milliseconds when detected. This task is sensitive to low doses of stimulants, nutritional factors, environmental conditions, and sleep loss.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cognitive Assessment: Psychomotor Vigilance Test (PVT)
PVT is a 10-minute test of simple visual reaction time used to assess alertness. Volunteers will be scored based on reaction time, correct responses, and lapses (failure to detect stimuli).
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cognitive Assessment: Matching to Sample
Matching to Sample assesses short-term spatial memory (working memory) and pattern recognition. Volunteers are presented with a series of 8x8 matrices. Each matrix is displayed for 4 seconds, volunteers see a blank screen for 8 to 16 seconds, and then 2 matrices will be presented: one matrix identical to the original, and another slightly different to the original. Volunteers have 15 seconds to select the correct comparison matrix. Volunteers will be scored by correct responses, reaction time, and time-out errors.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cognitive Assessment: Grammatical Reasoning
Grammatical reasoning assesses language-based logical reasoning. Volunteers will be presented with either the letters "AB" or "BA" followed by a statement that describes the order of the two letters (e.g. "A precedes B"). The volunteer must select whether the statement is true or false. Volunteers are scored based on accuracy and reaction time, with a max score of 32 correct responses.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cognitive Assessment: Go/No-Go Task
The Go/No-Go Task is a 10 minute test that assesses response inhibition. Volunteers will randomly be presented with with a "+" or "x" on their screen during moderate exercise on a stationary bike. Volunteers will be instructed to press a button as quickly as possible in response to one visual stimulus, and withhold a response to the other visual stimulus. Number of correct responses, incorrect responses, and reaction time will be scored.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cognitive Assessment: N-Back Task
The N-Bask Task is a 10 minute assessment of working memory. Volunteers will be shown a series of letters on a screen while performing moderate exercise on a stationary bike and asked to mentally take note of the letters shown. Volunteers will then be asked to respond "yes" or "no" by pressing the respective button if the letters currently displayed are the same letters that were displayed either 1, 2, and/or 3 letters back. Correct and incorrect responses will be recorded as a volunteer score.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Cognitive Assessment: Task-Switching Task
Task-Switching is a 10 minute assessment of cognitive flexibility. Volunteers will switch back and forth randomly between determining if the number presented on the screen is odd or even or if the number presented is above or below 5 while performing moderate exercise on a stationary bike. Volunteers will decipher which task is being performed based on the color of the number presented (pink or blue), and press the corresponding button on their keypad (odd/even or greater than/less than). Volunteers will be scored based on number of correct responses.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Physical Performance: Grip Strength
Grip strength will be measured in both hands to evaluate manual performance under cold stress using a hand dynamometer. Volunteers were asked to hold the dynamometer in a neutral position (shoulder adducted, elbow flexed to 90 degrees, forearm and wrist neutral) and instructed to squeeze the handle as hard as possible while maintaining a neutral position. Three repetitions will be completed for each hand, alternating hands between each trial. Grip strength for each hand was scored as the mean of the 3 trials, recorded in kilograms.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Secondary outcomes (11)
Cognitive Assessment: Balloon Analogue Risk Task (BART)
The BART is used to assess risk-taking behavior, reportedly altered by sleep loss. Volunteers will repeatedly fill simulated balloons with air, and points are awarded each time the balloon inflates with air without "popping it". The more the balloon is inflated, the more points are earned. Volunteers can bank their points at any time. All points accumulated that are not banked will be lost if the balloon pops. Simulated balloons will randomly pop after either 8, 32, or 128 puffs. Volunteers will be scored based on how many balloons are popped in each of these categories.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Assessment of Blinding
Volunteers will complete a single item exit survey at the end of the second experimental visit to assess the potential of the placebo effect on cognitive and physical performance during cold exposures. Volunteers will be asked to report which experimental session they believe they consumed Modafinil, answering either: session 1, session 2, or not sure.
Measured: Cold Exposure (Day 7)
Dietary Intake
Volunteers will be prescribed a standardized diet (1.2 g/kg protein, 6 g/kg carbohydrate, 1 g/kg fat) to moderate the potential influence of diet on performance during the experimental visits. Diet prescription will be based on volunteer body mass measured at the first familiarization visit. Volunteers will start diet prescription 48 hours prior to the first experimental visit at baseline assessment, and continue study diet through completion of second experimental visit (8 days total). Study dieticians will prepare individual diets derived from military combat rations (MRE; Meal, Ready-to-Eat) and commercially available food items. Dietary intake will be verified by collecting wrappers/containers and any food or drink that is not entirely consumed will be weighed and accounted for.
Measured: Baseline Assessment (Day 0) to Cold Exposure (Day 7)
Cold Exposure: Environmental Symptoms Questionnaire (ESQ)
The ESQ was used to determine the effects of exposure to environmental extremes. A modified version of the ESQ was used to assess the effects relevant to cold exposure only. Volunteers were asked to rate statements on a scale from 1 (not at all) to 5 (extreme). Higher scores indicate that the volunteer is experiencing more severe symptoms of cold exposure.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Profile of Mood States Questionnaire (POMS 2-A)
The POMS is a 65-item inventory of mood states that asks volunteers to rate each mood-related adjective on a 5-point scale (0-4) based on how the volunteer is currently feeling. Mood states will be measured on 7 sub-scales: 1) tension/anxiety [TA], 2) depression/dejection [DD], 3) anger/hostility [AH], 4) vigor/activity [VA], 5) fatigue/inertia [FI], 6) confusion/bewilderment [CB], and 7) friendliness. Subscales 1-6 have a potential score of 0-44, while the friendliness subscale has a potential score of 0-40. Total mood disturbance is calculated as: [(TA + DD + AH + FI + CB) - VA] with a potential score of 0-176 . Higher scores indicate that the individual experiences more intense or more frequent negative mood states compared to the general population.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Buss-Perry Aggression Questionnaire
The Buss-Perry Aggression Questionnaire is a 29-item questionnaire that assesses aggressive impulses and thought patterns. Volunteers rank statements on a 5-point scale from "extremely uncharacteristic of me (1)" to "extremely characteristic of me (5)." Aggression is scored on 4 scales: 1) physical aggression, 2) verbal aggression, 3) anger, and 4) hostility. Volunteers are scored for each subscale: physical (scored 9-45), verbal (scored 5-25), anger (scored 7-35), and hostility (scored 8-40), as well as a total score of all items (scored 29-145). Higher scores indicate greater overall aggression.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Felt Arousal Scale (FAS)
The FAS is a one-item inventory measuring feelings of arousal ranging from 1 (low arousal) to 6 (high arousal). Volunteers will be asked to rate their current level of arousal in the final minute of the 15-minute bout of moderate exercise on a stationary bike. Higher scores indicate higher levels of arousal.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Feeling Scale (FS)
The FS is a one-item inventory measuring the extent to which pleasant or unpleasant feelings are currently experiencing. The FS ranges from 5 (very good) to -5 (very bad). Volunteers will complete the FS in the final minute of the 15 minute bout of moderate exercise on a stationary bike. Higher scores indicate the volunteer is experiencing more pleasant feelings while lower scores indicate the volunteer is experiencing more unpleasant feelings.
Measured: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Resilience: Connor-Davidson Resilience Scale (CD-RISC-25)
The CD-RISC-25 was administered at the start of the first familiarization day to assess volunteer resilience as a potential moderating psychological factor. Volunteers were asked to rate 25 items on a scale from "not true at all" (0) to "true nearly all the time" (4). Scores can range from 0-100, with higher scores reflecting greater resilience.
Measured: Familiarization 1 (Day -2)
Background Survey
A background survey will be administered at the start of the first familiarization day. Volunteers will be asked to report basic demographic information, tobacco and supplement use, military service, recent physical activity habits, and previous experience with cold exposure as potential moderating variables of cognitive and physical performance during experimental visits.
Measured: Familiarization 1 (Day -2)
Adverse Events
Participants were asked to report any adverse events they may have experienced in the 24 hours following completion of 26-hour overnight cold exposures. Study staff met with volunteers to complete an in-person assessment the morning after overnight collection (Days 4 and 8) and provided a list of expected adverse events associated with Modafinil and sleep deprivation, as well as asked to report any other events/symptoms. Volunteers were asked to report whether they had experienced: trouble sleeping, nausea/other GI issues, headache, numbness or pain in fingers, numbness or pain in toes, other (specify), or no adverse event.
Measured: Post Overnight Chamber Exposures (Days 5 & 8)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Sep 2026
- Study start18 Feb 2025
- Primary completionOct 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Sleep DeprivationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 33 participants (estimated)
Sponsor and investigators
- Lead sponsor
- United States Army Research Institute of Environmental Medicine
- Sponsor type
- US federal agency
- Collaborators
- U.S. Army Medical Research and Development Command
- Responsible party
- Principal investigator, Harris R. Lieberman, United States Army Research Institute of Environmental Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07830056
- Sponsor's protocol ID
- 23-19HC
- Status last verified
- Sep 2026
- First submitted
- 6 Mar 2026
- Last updated
- 21 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 21 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Modafinil to Optimize the Performance of Cold-Stressed Sleep-Deprived Personnel
- ClinicalTrials.gov ID
- NCT07830056
- Acronym / sponsor ID
- 23-19HC
- Conditions
- Sleep Deprivation, Cold Exposure
- Keywords
- Modafinil, sleep deprivation, cold stress
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 33 participants (estimated)
- Lead sponsor
- United States Army Research Institute of Environmental MedicineUS federal agency
- Collaborators
- U.S. Army Medical Research and Development Command
- Study start
- 18 Feb 2025 (actual)
- Primary completion
- Oct 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 21 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Environmental and workplace stressors are common and often unavoidable in military operations. Two critical stressors are cold stress and sleep loss. They both can substantially degrade operational effectiveness. Various countermeasures are available to mitigate the adverse effects of these stressors, but due to operational requirements many are of limited use in the field. Modafinil is a drug that mitigates the effects of sleep deprivation and potentially cold stress, and modafinil may prevent performance degradation due to the combination of these stressors. This study will help determine if modafinil alters body-heat production and prevents cognitive and physical performance degradation due to cold stress in rested and sleep-deprived volunteers.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Drug: 200 mg Microcrystalline Cellulose200 mg Microcrystalline Cellulose |
| Modafinil | Active comparator | Drug: Modafinil (M)200 mg Modafinil |
Who may qualify
- Ages
- 17 to 39 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (6 listed)
- Healthy, men and women aged 18-39 years old. Active-duty military personnel who are 17 years of age will also be allowed to participate.
- Willing to refrain from the use of caffeine - including dietary supplements that contain caffeine - alcohol, and nicotine 24 hours prior to data collection.
- Willing to refrain from vigorous physical activity 24 hours prior to data collection.
- Willing to refrain from any dietary supplement use within one week of initial screening and at any time while enrolled in the study (except a multi-vitamin containing up to 100% RDA).
- Willing to consume study diets throughout the course of the study.
Key exclusion criteria (25 listed)
- Use of modafinil or armodafinil in the last 3 months.
- Known allergy to modafinil or armomodafinil.
- Current medical profile, or condition, that limits, compromises, or is likely to render inconsistent performance with Grip Strength, Finger Tapping, or cardiovascular exercise on an exercise bike.
- a. Individuals taking substances that directly interact with modafinil, alertness/attention/concentration, or sympathetic tone: stimulants; decongestants, barbiturates, bronchodilators; SNRIs; opioids; appetite suppressants; anti-obesity medications; b. Individuals taking substances which inhibit CYP3A4 (penicillins; macrolide antibiotics; fluoroquinolones; lomitapide; goldenseal) or MAO inhibitors.
- Females who are pregnant or breastfeeding, have a positive- pregnancy test, or plan on becoming pregnant in the next 3 months.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Modafinil (M)Evaluating the effect of Modafinil under both sleep deprivation and acute cold exposure on thermoregulation, cognitive flexibility/performance, and dexterity. | Drug | Modafinil |
| 200 mg Microcrystalline CellulosePlacebo intervention to compare to modafinil intervention. | Drug | Placebo |
Primary outcome
Height (in)
Time frame: Familiarization 1 (Day -2)
Height will be measured in inches using a stadiometer.
Body Weight (kg)
Time frame: Familiarization 1 (Day -2)
Body weight will be measured in kilograms using a calibrated electronic scale.
Body Composition: DXA Fat Mass (lbs)
Time frame: Familiarization 1 (Day -2)
Fat mass will be measured in kilograms via dual x-ray absorptiometry and used to calculate body fat percentage (fat mass/body weight).
Body Composition: DXA Lean Mass (lbs)
Time frame: Familiarization 1 (Day -2)
Lean mass will be measured in pounds using dual x-ray absorptiometry.
Body Composition: DXA Bone Mineral Content (lbs)
Time frame: Familiarization 1 (Day -2)
Bone mineral content (BMC) will be measured in pounds using dual x-ray absorptiometry.
Sleep & Physical Activity
Time frame: Familiarization 1 to Study Completion (11 Days)
Physical activity and sleep duration will be recorded in minutes per day with a wrist actigraphy monitoring system (Actiwatch Spectrum Plus, Koninklijke Philips N.V., Amsterdam, NL or equivalent device). The accelerometer will be placed on the volunteer's wrist on the first familiarization day, worn continuously throughout the entirety of study participation (11 days total), and returned after a 2-day washout period after the second overnight collection. Activity and sleep measurements recorded by the accelerometer will be utilized to determine sleep/wake times of volunteers throughout the study duration.
Cold Exposure: Core Temperature
Time frame: Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Core temperature will be measured continuously at baseline (room temperature) and during cold exposure using a telemetric thermometer capsule (e-Celsius® Performance Capsule, BodyCap, Saint-Clair, France, or similar). Volunteers will either insert the capsule as a rectal suppository the morning of testing, or opt to ingest orally the night (at least 12 hours) prior to data collection to ensure deep core body temperature is accurately monitored. Volunteers will be removed from testing if core temperature decreases to 35 degrees Celcius or lower.
Cold Exposure: Skin Temperature
Time frame: Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Skin temperature will be continuously measured in Celcius at baseline (room temperature) and during cold exposure using Thermochron iButtons attached at the volunteer's chest, triceps, hand, thigh, calf, and foot.
Dexterity: Finger Tapping Task (FTT)
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
The FTT is an approximately 10 minute test used to assess manual dexterity and visuomotor coordination. Volunteers are asked to follow simply motor commands using their hands and fingers while seated using a standard 8-finger QWERTY keyboard position (left fingers resting on ASDF, right fingers resting on JKL;). Volunteers are presented varying finger tap sequences on a computer displaying spatially compatible keys matching the standard position (ASDFJKL;) and asked to press the corresponding key while wearing Army issued contact gloves. The presentation time of cues will be adjusted throughout the task at variable difficulties to assess visuomotor response thresholds. Volunteers are scored based on how quickly finger taps are correctly executed in the presented sequence without errors of omission, commission, or excursions.
Cognitive Assessment: Scanning Visual Vigilance
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Volunteers will continuously scan a computer screen to detect stimuli that are present in irregular intervals approximately every 1 minute. Volunteers will be scored based on whether a stimulus is correctly detected (max score of 30), falsely detected, and the response time in milliseconds when detected. This task is sensitive to low doses of stimulants, nutritional factors, environmental conditions, and sleep loss.
Cognitive Assessment: Psychomotor Vigilance Test (PVT)
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
PVT is a 10-minute test of simple visual reaction time used to assess alertness. Volunteers will be scored based on reaction time, correct responses, and lapses (failure to detect stimuli).
Cognitive Assessment: Matching to Sample
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Matching to Sample assesses short-term spatial memory (working memory) and pattern recognition. Volunteers are presented with a series of 8x8 matrices. Each matrix is displayed for 4 seconds, volunteers see a blank screen for 8 to 16 seconds, and then 2 matrices will be presented: one matrix identical to the original, and another slightly different to the original. Volunteers have 15 seconds to select the correct comparison matrix. Volunteers will be scored by correct responses, reaction time, and time-out errors.
Cognitive Assessment: Grammatical Reasoning
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Grammatical reasoning assesses language-based logical reasoning. Volunteers will be presented with either the letters "AB" or "BA" followed by a statement that describes the order of the two letters (e.g. "A precedes B"). The volunteer must select whether the statement is true or false. Volunteers are scored based on accuracy and reaction time, with a max score of 32 correct responses.
Cognitive Assessment: Go/No-Go Task
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
The Go/No-Go Task is a 10 minute test that assesses response inhibition. Volunteers will randomly be presented with with a "+" or "x" on their screen during moderate exercise on a stationary bike. Volunteers will be instructed to press a button as quickly as possible in response to one visual stimulus, and withhold a response to the other visual stimulus. Number of correct responses, incorrect responses, and reaction time will be scored.
Cognitive Assessment: N-Back Task
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
The N-Bask Task is a 10 minute assessment of working memory. Volunteers will be shown a series of letters on a screen while performing moderate exercise on a stationary bike and asked to mentally take note of the letters shown. Volunteers will then be asked to respond "yes" or "no" by pressing the respective button if the letters currently displayed are the same letters that were displayed either 1, 2, and/or 3 letters back. Correct and incorrect responses will be recorded as a volunteer score.
Cognitive Assessment: Task-Switching Task
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Task-Switching is a 10 minute assessment of cognitive flexibility. Volunteers will switch back and forth randomly between determining if the number presented on the screen is odd or even or if the number presented is above or below 5 while performing moderate exercise on a stationary bike. Volunteers will decipher which task is being performed based on the color of the number presented (pink or blue), and press the corresponding button on their keypad (odd/even or greater than/less than). Volunteers will be scored based on number of correct responses.
Physical Performance: Grip Strength
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Grip strength will be measured in both hands to evaluate manual performance under cold stress using a hand dynamometer. Volunteers were asked to hold the dynamometer in a neutral position (shoulder adducted, elbow flexed to 90 degrees, forearm and wrist neutral) and instructed to squeeze the handle as hard as possible while maintaining a neutral position. Three repetitions will be completed for each hand, alternating hands between each trial. Grip strength for each hand was scored as the mean of the 3 trials, recorded in kilograms.
11 secondary outcomes
Cognitive Assessment: Balloon Analogue Risk Task (BART)
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Assessment of Blinding
Time frame: Cold Exposure (Day 7)
Dietary Intake
Time frame: Baseline Assessment (Day 0) to Cold Exposure (Day 7)
Cold Exposure: Environmental Symptoms Questionnaire (ESQ)
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Profile of Mood States Questionnaire (POMS 2-A)
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Buss-Perry Aggression Questionnaire
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Felt Arousal Scale (FAS)
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Mood Assessment: Feeling Scale (FS)
Time frame: Familiarization 1 (Day -2), Familiarization 2 (Day -1), Baseline Assessment (Day 0), Cold Exposure (Days 2 & 3), Cold Exposure (Days 6 & 7)
Resilience: Connor-Davidson Resilience Scale (CD-RISC-25)
Time frame: Familiarization 1 (Day -2)
Background Survey
Time frame: Familiarization 1 (Day -2)
Adverse Events
Time frame: Post Overnight Chamber Exposures (Days 5 & 8)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Sep 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Modafinil (M) and 200 mg Microcrystalline Cellulose in people with Sleep Deprivation and Cold Exposure, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 25 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 21 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Harris R Lieberman, PhD (508-206-2326, harris.r.lieberman.civ@health.mil), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Height (in) (time frame: Familiarization 1 (Day -2)). The study lists 17 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Sep 2026.