2B-Alert App 2.0: personalized caffeine recommendations for optimal alertness.

STUDY OBJECTIVES: If properly consumed, caffeine can safely and effectively mitigate the effects of sleep loss on alertness. However, there are no tools to determine the amount and time to consume caffeine to maximize its effectiveness. Here, we extended the capabilities of the 2B-Alert app, a unique smartphone application that learns an individual's trait-like response to sleep loss, to provide personalized caffeine recommendations to optimize alertness. METHODS: We prospectively validated 2B-Alert's capabilities in a 62-hour total sleep deprivation study in which 21 participants used the app to measure their alertness throughout the study via the psychomotor vigilance test (PVT). Using PVT data collected during the first 36 hours of the sleep challenge, the app learned the participant's sleep-loss response and provided personalized caffeine recommendations so that each participant would sustain alertness at a pre-specified target level (mean response time of 270 milliseconds) during a 6-hour period starting at 44 hours of wakefulness, using the least amount of caffeine possible. Starting at 42 hours, participants consumed 0 to 800 mg of caffeine, per the app recommendation. RESULTS: 2B-Alert recommended no caffeine to five participants, 100-400 mg to 11 participants, and 500-800 mg to five participants. Regardless of the consumed amount, participants sustained the target alertness level ~80% of the time. CONCLUSIONS: 2B-Alert automatically learns an individual's phenotype and provides personalized caffeine recommendations in real time so that individuals achieve a desired alertness level regardless of their sleep-loss susceptibility.

Increasing aggression during the COVID-19 lockdowns.

BACKGROUND: To combat the spread of COVID-19, many communities implemented restrictions on personal movement, often referred to as "lockdowns." We hypothesized that continued lockdowns might be associated with increased feelings of aggression. METHODS: Over the first six months of the COVID-19 pandemic, the Buss-Perry Aggression Questionnaire (BPAQ) was administered to a total of 5,928 adults distributed proportionally from across the United States during independent online cross-sectional surveys collected each month. Data across the 6-month period were compared between those under lockdown versus those not under such restrictions. RESULTS: BPAQ Total Aggression scores showed a significant main effect for both month and lockdown status as well as a significant interaction effect, with increasing scores evident for those reporting that they were under lockdown relative to those reporting no restrictions. This same pattern was evident for all four subscales of the BPAQ, including Physical Aggression, Verbal Aggression, Anger, and Hostility. LIMITATIONS: Random sampling of the entire population was not possible, so generalization of the results should be made with caution. Additionally, data were collected cross-sectionally and cannot be considered to reflect longitudinal change within individuals. Finally, the cross-sectional survey design means that it is impossible to infer that the lockdowns caused the increase in aggression. CONCLUSIONS: Lockdowns were associated with elevated levels of aggression that were higher in later months of the national pandemic response.