It now seems I was wrong?
encounters between Homo Sapiens and Neandertal have left their marks in the genome of modern Europeans, making many of us more prone to nicotine addiction and to depression. Around 3% on average of the modern Europeans' genome is inherited from our Neandertal ancestors. It may not seem like much (although we have not inherited more from our great-great-grand-mother) – but it packs a punch. It influences their risk of becoming addicted to nicotine as well as their tendency to depression, according to research published in Science magazine.

http://science.sciencemag.org/content/351/6274/737