🧠 The Impact of Stress on Aggression

Stress can trigger aggression not only as a defensive reaction but also as a way to reduce internal tension. This pattern is observed in both animals and humans and has a clear neurobiological basis.

🐁 In Animals

• In rats, stressors such as electric shocks lead to increased glucocorticoid levels and blood pressure.
• Chronic exposure can cause stress-induced gastric ulcers.
• One of the most effective ways for a rat to reduce stress is to bite another rat.
• This behavior suppresses the release of corticotropin-releasing hormone (CRH), which activates the hypothalamic-pituitary-adrenal (HPA) axis.

🐒 In Primates

• Among baboons, over 40% of aggression cases are classified as displaced aggression.
• Dominant males who redirect aggression after a defeat tend to have 15–20% lower glucocorticoid levels than those who do not.
• Displaced aggression serves both a social regulation function and helps reduce physiological stress in the aggressor.

👤 In Humans

• During the 2008–2009 economic recession in the U.S.:
  • Domestic violence incidents increased by 9–12% in some regions.
  • Police received more calls related to family conflict.
• A study of 900 NFL games in the U.S. showed:
  • After an unexpected loss of the local team, domestic violence incidents rose by about 10%.
  • If the loss occurred in a playoff game, the increase was 13%.
  • After a championship final loss, incidents rose by up to 20%.

🧬 Biological Mechanism

• Aggressive behavior activates dopaminergic reward pathways in the brain, producing short-term relief.
• This reduces hypothalamic activity and suppresses stress hormone release.
• In animals, this clearly reduces physiological markers of stress; in humans, it may create a subjective sense of control or relief.