Many smokers will admit that seeing someone else smoking increases their own urge to light up. Now a new study has found that seeing other people using e-cigarettes also appears to increase the urge to light up among young smokers.

This increased urge is as strong as if they were looking at someone smoking a regular cigarette.

E-cigarettes are battery-powered devices designed to supply nicotine through inhaled water vapour. They are currently at the centre of a major debate, with some people stating that they can help smokers to quit the habit and others insisting that they are potentially harmful to health.

As a result of potential health concerns, the HSE introduced a ban on e-cigarettes in all hospitals and health facilities from May 1. It said this ban 'followed a detailed review of their safety' and insisted that ‘there currently is no conclusive evidence that e-cigarettes are safe for long-term use, or are effective as a smoking cessation aid'.

While studies are ongoing into the health effects of e-cigarettes, until now, there have been no studies on the visual effects of using them.

US scientists decided to investigate this further. Their study involved 60 young adult smokers, each of whom was paired with an actor pretending to be a participant. During the course of a conversation between the smoker and actor, the actor would smoke either a real cigarette or an e-cigarette.

The urge of the smokers to light up themselves before, during and after this interaction was analysed.

The study found that seeing someone else smoking significantly increased the urge of the young smokers to light up themselves, irrespective of whether it was a real or e-cigarette.

As a control, some of the actors drank from a bottle of water to mimick alternative hand-to-mouth behaviour. The urge to light up among the smokers did not increase when they saw this behaviour.

"Whether participants were exposed to someone smoking a combustible or an e-cigarette, the urge to smoke a combustible cigarette was just as high in either condition. We know from past research that seeing regular cigarette use is a potent cue for someone to want to smoke. We did not know if seeing e-cigarette use would produce the same effect. But that is exactly what we found," the researchers from the University of Chicago said.

They also pointed out that when they re-tested the smokers 20 minutes after being exposed to someone else smoking, the urge to light up ‘remained elevated'.

They warned that ‘there could be effects of being in the company of an e-cigarette user, particularly for young smokers'.

"For example, it's possible that seeing e-cigarette use may promote more smoking behavior and less quitting."

Details of these findings are published in the journal, Tobacco Control.