Heroin and related drugs made up 55 percent of the more than 40,000 drug arrests in the state in 1998, according to Maryland State Police statistics.

Police arrested 22,749 people in 1998 on charges of possession and sale of heroin and related drugs, an 11 percent increase from the 20,580 arrested in 1997. Marijuana arrests, by contrast, totaled 17, 445 in 1998 and 16,007 in 1997. Marijuana is a "primary substance of abuse" and its use typically leads other drugs, authorities said.

Exact numbers of heroin arrests are hard to come by, since the drug is lumped in with opium, cocaine and its derivatives. But Maryland State Police said they have noticed an increase in heroin use throughout the state.

They could not say why heroin use is growing, however.

"If I knew that answer, it would get solved," said Lt. Joe Barker, a state police spokesman.

The increase could be partly attributable to the overall increase in drug arrests: The 41,489 arrests in 1998 represented a 7 percent increase from 1997.

But officials at the Center for Substance Abuse Research (CESAR) in College Park said the one reason for the growth in heroin arrests is the fact that use of the drug is expanding from Baltimore City into more suburban areas.

Arrests for possession of heroin-class drugs increased in 13 counties and Baltimore City from 1997 to 1998, according to state police data. Eleven counties had an increase in arrests for sale and manufacturing in that category.

"It used to be a drug seen just in Baltimore City but it's showing up in suburban counties," said Erin Artigiani, coordinator of CESAR's Drug Early Warning System. "It's not just a city drug anymore."

More users are taking heroin by sniffing it instead of injecting it with needles that put them at risk for contracting AIDS, authorities said. But the drug is dangerous no matter how it is used and causes irregular blood pressure, a slow heart rate and sedation that could lead to a coma, Artigiani said.

One reason for heroin's increased popularity is that it has become more powerful in the past 10 years, according to the Drug Policy Foundation in Washington, D.C. But there is no concrete explanation for the spread of heroin; the numbers "rise and fall depending on the year"

"It's hard to really get into people's minds and say why certain drugs become popular at certain times," said Ted Bridges, policy analyst for the Drug Policy Foundation. "I just think these things have always been here and are here to stay. I really don't think there is a way to govern perceptions per se."

Perceptions have little to do with why people turn to drugs, said Terry D. Blumenthal, psychology professor at Wake Forest University. He said drugs look like a better option to people who lack reinforcers, or things that make them feel good.

During the Vietnam War, many American soldiers were addicted to heroin when they were overseas, but they were able to quit entirely when they returned home, he said.

"It's ... partly because they had other things they could use as reinforcers, like family and friends," Blumenthal said. "If we could provide those people with other things, they may be less likely to use drugs."

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