New York, Jan 16 (IANS): Watching someone smoke a vape pen -- the new generation e-cigarette -- may trigger an immediate, significant and lasting increase in the desire to smoke among teenagers, as similar as watching someone smoke a "combustible" tobacco cigarette, a new study has found.

The findings showed that the increased desire may extended even to people who had never used the newer device.

"The new e-cigarettes, known as vape pens, are now larger and more powerful devices," said study director Andrea King, professor at the University of Chicago.

Although vape pens -- a second-generation electronic nicotine-delivery system (ENDS) -- look different but they share too many salient features of the act of smoking -- including inhalation, exhalation and hand-to-mouth behaviours.

"This makes them a potent trigger, encouraging people to smoke. Their impact is roughly equal to watching someone light up a cigarette. The make the young adults want to smoke," King added.

Despite initial hopes that e-cigarettes and now vape pens, could help smokers break away from tobacco, studies have not been able definitively to confirm that they contribute to smoking cessation efforts, the researchers noted.

For the study, the team conducted an experiment described as "assessing mood response to commons tasks" on 108 young adults, men and women aged 18 -35 -- a highly susceptible group.

During the experiment, one group smoked either a combustible cigarette or a vape pen. Both cues increased desire among research subjects for a cigarette or an e-cigarette.

The level and duration of desire to smoke among volunteers was the same whether they observed their "colleague" smoking a cigarette or using a vape pen.

The study was published in the journal Nicotine and Tobacco Research.