E-cigarettes are the latest in a long line of products hailed as potential substitutes for the conventional tobacco cigarette.

“They are different from any of the products I have seen before,” said Eissenberg, who is director of VCU’s clinical behavioral pharmacology laboratory and has been studying novel tobacco products since the late 1990s.

While early versions of e-cigarettes delivered very little nicotine, the latest varieties seem more powerful in their ability to suppress withdrawal symptoms and substitute for conventional cigarettes, he said.

Yet as sales of e-cigarettes grow, approaching an estimated $2 billion a year in the United States alone, public health officials are wary because the long-term health effects of e-cigarettes are unknown.

Eissenberg said the research that VCU is conducting will be useful in understanding e-cigarettes as well as other alternative tobacco- and nicotine-delivery products that are on the market now or will be in the near future.

“There is a whole list of unanswered questions and a whole list of products that we need to apply our methods to,” he said.

In the next few months and years, thousands of vapers are expected to spend time at VCU as volunteer research subjects.