It’s hard to quit one without the other (Image: Sipa Press/Rex Features)

If drinking and smoking seem inextricably linked, perhaps it’s because in the brain’s pleasure centre they actually are.

Alcoholics often have a particularly hard time quitting cigarettes. Traute Flatscher-Bader at the University of Queensland in Brisbane, Australia, and colleagues wondered why this should be. So they did a post-mortem analysis of gene expression in the brains of smokers, alcoholics and those who had done both during their lives.

They found that a group of genes in the nucleus accumbens – an area involved in creating pleasurable …