Tobacco has long been recognised as the main ‘gateway drug’ and new research has suggested that smokers are more inclined to crave cocaine.

The authors — epidemiologist Dr Denise Kandel, who first identified the ‘gateway drug’ concept in 1975 and her husband, Nobel Prize-winning neurobiologist Dr Eric Kandel — discovered that mice addicted to nicotine were 78 per cent more likely to seek out cocaine in lab experiments.

The Kandels and their colleagues at Columbia University also found that nicotine caused long-lasting epigenetic changes that significantly boosted the animals’ response to cocaine....