Scientists investigated concerns that statins are linked to an increase in violence and found that the effect was strong in women over 45 who had not previously shown a tendency towards aggression.
In the first randomised trial to investigate the effect, more than 1,000 men and post-menopausal women took either statins or a placebo over six months.
Researchers found that those on statins who struggled to get to sleep appeared to be most at risk of a surge in aggression, 'The Times' reported.
"Many studies have linked low cholesterol to increased risk of violent actions and death from violence, defined as death from suicide, accident and homicide," she said.
Other studies had indicated that the drugs were associated with lower levels of aggression than earlier treatments.
Researchers do not know why the drugs appear to make women more violent, although it may be linked to sleep loss. Men, on the other hand, may benefit from a drop in their testosterone levels.