TRENTON, N.J. (AP) -- Heroin is used by 18- to 25-year-olds in New Jersey at more than twice the national average, and officials who released a report on drug abuse Monday said the highly addictive drug is easy to get in the Garden State.

While marijuana was reported to be the most-tried illegal drug in the state, the federally funded report showed that 5 percent of the younger adults had heroin habits, compared to 2.5 percent nationally.

New Jersey's shipping ports, small geographic size and high population density make distributing heroin easier here than in other states, said Carolann Kane-Cavaiola, assistant commissioner for the state's Division on Addiction Services.

"We're the first ones that get it," Kane-Cavaiola said. "In New Jersey, the DEA (U.S. Drug Enforcement Administration), along with other law enforcement and emergency rooms know that we have the best and cheapest heroin in the country."

The results of the 2003 New Jersey Household Survey on Drug Use and Health have prompted officials to plan to open two more methadone clinics, in Ocean and Gloucester counties. The expansion is the first in more than a decade and will bring to 36 the number of centers around the state where heroin addicts can receive drugs to be weaned off heroin.

The survey, conducted in 2002 and 2003, found marijuana was the most used illegal drug in New Jersey, with 30 percent of those surveyed reporting that they tried it at least once. The national average is 40.6 percent.

The younger a person first uses marijuana, the greater the likelihood they'll use other drugs later in life. Eighty-three percent of those who first tried pot at age 11 or younger reported using other drugs in their lives.

"Marijuana, we're concerned about because it is the most frequently used even though we're below the national average. It's being used by young children and it starts out innocently, and it becomes a gateway to more serious (drugs)," said Ed Rogan, spokesman for the Department of Human Services.

Cocaine, hallucinogens and non-prescribed stimulants and pain relievers followed marijuana use, respectively. Use of drugs such as crack, steroids, ecstasy, sedatives, methamphetamines and tranquilizers were the least reported.

"We need to continue to focus our efforts on preventing drug abuse among young people," said Human Services Commissioner James M. Davy. "Delaying the age of onset of abuse has a significant impact on drug use later in life."

The report found that New Jerseyans are smoking more cigarettes but drinking less alcohol and using less illegal drugs than they were in the 1990s. But because the adults surveyed were interviewed over the phone, illegal drug use is likely to be seriously underreported, according to the survey. Estimates for residents having had alcohol (87 percent) or smoked cigarettes (58 percent), often more socially accepted behaviors, were expected to be more accurate.

Residents also lag behind the rest of the country in getting treatment, a serious concern for officials since drugs are a major factor in child abuse, poverty and homelessness, and can contribute to mental illness. Those treated for drug addiction, including alcohol and tobacco, are expected to increase from 61,000 in 2003 to 65,000 in 2006.

The report also delved into side effects from the Sept. 11, 2001 attacks on New Jerseyans. More than 50 percent surveyed said they experienced some type of psychological symptom, including post-traumatic stress disorder and depression. Women, people aged 26 to 34, and those who knew someone injured or killed, or who lived closest to New York were most likely to report symptoms.

Copyright 2005 The Associated Press. All rights reserved.