People with lower cholesterol levels are more likely to die violent deaths.
If you put primates on a low-cholesterol diet, they become more aggressive. Lowering animals’ cholesterol seems to affect their levels of serotonin. Even fruit flies start fighting if you interfere with their serotonin levels.
Studies have linked serotonin levels in people to violence, impulsivity, suicide, and murder.
In a randomized controlled trial, statins were found to increase aggression in post-menopausal women though, oddly, not in men. Giving statins to Nile tilapia made them more confrontational and altered the levels of serotonin in their brains.