The ancient custom of smoking hookah hasn’t typically raised health concerns among college students.

But recent studies reveal that this pastime poses more risks than people realize, according to Michael C. Miller, an assistant professor of psychiatry at Harvard Medical School.

Miller, the editor in chief of the Harvard Mental Health Letter, which discusses the hookah findings in its March issue, said he is concerned about students who think hookah smoke is less harmful than cigarette or marijuana smoke.

“The nature of hookah smoking is that you inhale deeply and hold on to tremendous amounts of smoke—not like taking a little puff on a cigarette, which is dangerous enough,” he said.

A scientific study mentioned in the Mental Health Letter estimated that water pipe smokers inhale the equivalent of 100 cigarettes or more during a single smoking session.

“I wouldn’t say it’s more addictive,” Miller said of hookah versus cigarettes. “But the perception somehow is that it’s safe,” he added. “People think it’s safe, but it’s not.”

Todd G. Steinbach, sales clerk at Leavitt & Peirce Tobacco, a smoke shop in Harvard Square, cited the taste of hookah as a likely explanation for the perceived harmlessness of hookah smoking.

“The tobacco that goes into hookah is a different blend, so it is not seen as damaging,” he said.

The creative designs of water pipes also enhance the appeal of hookah, he added.

Hatim H. Eltayeb ’09 said that hooking smoking is popular among Harvard students because of its social component.

“Freshman year we used to sit outside John Harvard and smoke sheesha,” Eltayeb said, using another term for hookah. “That’s how a lot of people got to know each other.”

Jaime S. M. Guarnaccia ’08 said that smoking hookah also used to bring him and his friends together.

“People like blowing smoke,” he said. “It’s a fun thing to do. It’s exotic and foreign, and people like that.”

But Guarnaccia said he has quit smoking hookah for the same reason he quit smoking cigarettes.

“I just didn’t want to do that to my lungs anymore,” he said.