Risk for Suicide and Homicide Peaks at Night: Findings From the National Violent Death Reporting System, 35 States, 2003-2017.

Objective: The Mind after Midnight hypothesis proposes that nocturnal wakefulness increases the risk for dysregulated behaviors. Prior studies highlight a greater risk for suicide at night after adjusting for population wakefulness. How this risk varies hour to hour, differs across subgroups, or applies to other behaviors is unknown.Methods: Data on 78,647 suicides and 50,526 homicides from the National Violent Death Reporting System were combined with population wakefulness data for 2003-2017 from the American Time Use Survey. Hourly incident risk ratios (IRRs) were estimated after adjusting for population wakefulness. Two-way analysis of variances identified significant time-by-subgroup interactions that were quantified in post hoc analyses.Results: Suicide counts peaked at 12:00 PM, while homicide counts peaked at 10:00- 11:00 PM. Adjusting for demographics and population wakefulness revealed a 5-fold greater risk for suicide at 3:00 AM (aIRR: 5.20 [4.74-5.70]) and an 8-fold greater risk for homicide at 2:00 AM (aIRR: 8.04 [6.35-10.2]). Hourly risk for suicide varied by age, ethnicity, blood alcohol level, and current partner conflict. Hourly risk for homicide varied by sex and blood alcohol level.Conclusions: Risk for suicide and homicide is greater at night than expected based on the number of people awake at that time. Nighttime risk was greater among young adults and those intoxicated with alcohol, but not among those with a history of suicidal ideation or attempts. Further research should evaluate mechanisms of risk and confirm these findings at an individual level.

The Psychological Effects of Short-Term Fasting in Healthy Women.

OBJECTIVE: The study aimed to investigate affective responses to 18-h fasting in healthy controls. In particular, the study focused on self-reported mood, irritability, sense of achievement, reward, pride, and control. METHOD: Participants were a non-clinical sample of 52 women with a mean age of 25. A repeated-measures design was used, whereby participants provided diary measures of psychological variables throughout both 18-h fasting and non-fasting periods. RESULTS: Fasting led to increased irritability, and also to positive affective experiences of increased sense of achievement, reward, pride, and control. DISCUSSION: Even short-term fasting in healthy controls can lead to positive psychological experiences. This lends support to cognitive-behavioral and cognitive-interpersonal models of ANR, which suggest that dietary restriction is maintained through positive reinforcement.