An unprecedented number of older people are using illegal recreational drugs in the US, according to a study which has revealed a 70 per cent spike in cannabis use among Baby Boomers in the past decade.

“For years we’ve been worried about the potential effects of marijuana on the developing brains of teens, but now we may need a bit more focus on their grandparents, who are increasingly more likely to be current users,” said Dr Joseph J. Palamar of New York University, one of the lead authors of the study.

Eight states, including Colorado and Oregon, as well as Washington DC allow recreational marijuana use, while 28 have approved medical programmes.

Researchers investigated cannabis use among over-50s by evaluating responses from 47,140 US adults who took part in the National Survey on Drug Use and Health. The study published in Addiction revealed a 71 per cent increase in marijuana use among adults between 2006 and 2013, particularly among those aged between 50 and 64. Men were also shown to be more likely to use the drug than women. [Read more at Independent]