Too much coffee can induce aggression and paranoia By Roger Dobson 26 October 2003 People who drink too much coffee are at risk of caffeine psychosis, according to a new report. It found that too much caffeine can lead to marked changes in personality and make drinkers more aggressive, anxious and temperamental. "Caffeinism" puts sufferers at further risk of anxiety neurosis, irregular heart beats, insomnia, muscle twitches, and nervous irritability. The warning comes a week after Tony Blair suffered an irregular heart beat, which he reportedly blamed on too much strong continental coffee at the European Union summit in Brussels....