More than a million American men sought inpatient treatment for substance abuse in 2011 — twice the number of women, according to the federal government.

Yet, no difference in substance dependence emerged among boys and girls ages 12 to 18, after researchers at the Substance Abuse and Mental Health Services Administration (SAMHSA) ran the numbers. Whereas American teenage boys tend to abuse marijuana, teenage girls tended to abuse alcohol in greater numbers.

And then young women ages 18 to 24 pulled ahead of their male counterparts in marijuana abuse, with twenty-two percent reporting pot as their preferred substance of abuse, compared to three percent of men — who seemed to prefer alcohol at that point.

Report Details Gender Differences In US Substance Abuse Rates The U.S. government released a report this week describing gender differences in substance abuse.

SAMHSA also reported that elderly women were nearly three times as likely to abuse prescription pain relievers such as oxycodone than men their age, suggesting that public health policymakers focus a bit on gender differences in substance abuse.

Although the data doesn’t explain the causes of variability in substance abuse, researchers said they hoped to inform the design of social services for specific groups based on sex and age across multiple settings, including the doctor’s office. Clinicians and policymakers might note, for example, research finding that women begin using methamphetamine at younger ages than men.

“This research, coupled with the findings in this report, might suggest that age-appropriate methamphetamine prevention and outreach efforts directed towards adolescents and young women in particular may be important in areas with moderate to high rates of methamphetamine use,” the researchers wrote. “Additionally, the findings related to differences in the abuse of prescription pain relievers between older adult males and females may warrant further investigation.”

Among other findings, the researchers noted a negligible difference in prescription painkiller abuse rates for young men and women ages 18 to 34. Among Americans ages 25 to 34, 19 percent of women admitted to abusing oxycodone and similar pills, compared to some 12.2 percent of men that age.

“The only meaningful difference by effect size between males and females was observed among admissions aged 65 or older,” the researchers said. Elderly women abused such drugs nearly three times as often as men their age, at 7.2 percent compared to 2.8 percent.