From the article: A lack of quality sleep can cause aggressive behavior, according to recent longitudinal findings published in the journal Biological Psychology. Brain imaging data revealed that the effect may be related to reduced activity in the prefrontal cortex and increased activity in the limbic regions.

Good sleep is paramount to the healthy functioning of our brains and bodies. Studies have shown that a lack of quality sleep can hinder our ability to regulate our thoughts and emotions and inflict consequences on our behavior. One of these consequences might be increased aggression.

While multiple studies have indicated a link between poor sleep and aggressive behavior, the direction of this relationship remains unclear — does poor sleep actually cause aggressive behavior? Study authors Haobo Zhang and Xu Lei conducted a longitudinal study to attempt to answer this question. Through neuroimaging data, they also explored the potential brain mechanism responsible for the relationship between sleep and aggression.

“As sleep plays an important role in the physical and mental health of individuals, we thought to uncover the causal relationship and mechanisms between sleep quality and aggressive behaviour in order to raise public awareness of the importance of sleep,” said Lei, a professor and director of the Sleep and NeuroImage Center at Southwest University in China.

Zhang and Lei obtained data from the Behavioral Brain Research Project of Chinese Personality (BBP), an ongoing study of undergraduate students from Chongqing, China. They focused on data collected from two time points separated by two years. For the current analysis, the sample consisted of around 450 students between the ages of 16 and 26 years old.

At both time points, the participants completed an assessment of their subjective sleep quality in the past month, and a measure of aggression that included the sub-dimensions of hostility, physical aggression, impulsiveness, and anger. Students also underwent functional magnetic resonance imaging (fMRI) to measure their brain activity.