Kiwis who imbibe the caffeine equivalent of one and a half cups of espresso coffee – or seven cups of instant – are more likely to hallucinate according to a new study, which may explain the ascendant popularity of coffee culture in New Zealand.

Researchers at Durham University in the UK found that people with a caffeine intake of that level, whether from coffee, tea, caffeinated energy drinks, pills or chocolate; are three times more likely to hear voices and see things that aren’t there than those who consume a single short black, reports LiveScience.