A Durham University team questioned 200 students about their caffeine intake, the journal Personality and Individual Differences reported.
However, academics say the findings do not prove a "causal link".
They also stress that experiencing hallucinations is not a definite sign of mental illness and that about 3% of people regularly hear voices.
"This is the first step toward looking at the wider factors associated with hallucinations," said psychology PhD student Simon Jones, who led the study.
Could it be that anyone who drinks seven cups of instant coffee is already a little crazy? If you like coffee that much, invest in a real brewing machine! Link -Thanks, Jee!