Heroin and prescription drug abuse declined last year, according to a new government report, a bright signal of hope in the battle against one of the most devastating and politically explosive problems facing the nation.

Nevertheless, illicit use of certain other drugs rose, and drug use across all age groups increased between in 2018.

The Substance Abuse and Mental Health Services Administration reported Tuesday that drug use and abuse increased from 19% to 19.4% across all age groups starting at 12 years old in 2018. Marijuana is still the most popular drug, and its use increased. The drop in heroin use was marginal, and there was a small decrease in the use of cocaine as well.

But the number of people who misused opioids fell from 11.4 million to 10.3 million, a “significant decrease,” according to Dr. Elinore F. McCance-Katz, Assistant Secretary for Mental Health and Substance Use.

While Dr. McCance-Katz says the figures showing a decline in opioid and heroin use are “positive findings,” she says increased marijuana use in people aged 12 to 17, and 26 and older, is “problematic.”

Even so, marijuana use stayed the same on average among people between 18 and 25 years of age, an age group McCance-Katz says SAMHSA was especially focused on after previously seeing a marked increase in young people smoking pot.