More girls than boys are becoming first-time users of alcohol, cigarettes and marijuana, reversing previous trends, the U.S. drug czar said in a report released on Thursday.

“Girls have become users at rates that exceed boys or equal boys now, which never used to be the case,” John Walters, director of the White House Office of National Drug Control Policy, said in a telephone interview.

The report found 1.5 million U.S. girls 18 or under started using alcohol in 2004, compared with 1.2 million boys. It found that 730,000 girls started smoking cigarettes, compared with 565,000 boys, and 675,000 girls started using marijuana, compared with 577,000 boys.

Walters said there were several reasons why girls might turn more to drugs and alcohol than boys.

“They are more likely to be influenced by peer pressure, even when they have been told and accepted that these behaviors are risky for them,” Walters said.

“They are twice as likely to be victims of depression. They report that when they use, that they do that to improve their moods.”

The report, based on government surveys, found that 1.6 million girls reported having at least one major depressive episode in 2004. “That’s more than twice as many as boys,” the report reads.

Walters said girls often used drugs and cigarettes to try to stay slim.

He said parents should talk to children before they were at risk of drug use.

“It is not going to be a stranger or some sinister person who offers it,” Walters said. “It is going to be your best friend. We have to be sure to prepare them for how they are going to say no to their best friend.”