The U.S. Department of Justice has filed a lawsuit alleging that Forest Laboratories Inc. (FRX) improperly marketed antidepressant drugs Celexa and Lexapro for use in children and paid kickbacks to encourage doctors to prescribe the drugs.

The government's complaint, unsealed Wednesday in a Massachusetts federal court, alleges that Forest misled doctors and consumers by failing to disclose a medical study that determined the company's antidepressant drugs were ineffective for pediatric use. The study also found that the drugs could cause suicidal thoughts in children.

Despite the study's negative findings, Forest promoted its antidepressant drugs for pediatric use, citing instead a different medical study which found the drugs to have a positive effect on children suffering from depression, prosecutors said.

According to the lawsuit, senior executives at Forest, including company President Lawrence Olanoff, knew about the negative study in 2001 but never disclosed the information to Forest's sales representatives, its executive advisory board or to pediatric specialists hired to promote Celexa and Lexapro.

Forest spokesman Frank Murdolo said the company hasn't yet seen the lawsuit.

"When we see the complaint, we'll be better able to assess what the details are," Murdolo said. He said the company had previously disclosed that its marketing practices were under investigation by the Justice Department.

The U.S. Food and Drug Administration hasn't approved Celexa and Lexapro for pediatric use.

In addition to the marketing allegations, government lawyers allege that Forest lavished doctors with cash payments, expensive meals and other valuables to induce them to prescribe the antidepressants. The lawsuit alleges that the drug maker disguised the cash payments as grants and consulting fees.

The Justice Department also alleges that Forest's improper marketing of the antidepressants and the kickbacks caused false claims to be submitted to federal health-care programs.

The government is seeking triple money damages from Forest under the federal False Claims Act as well as other monetary penalties.

-By Brent Kendall, Dow Jones Newswires; 202-862-9222; brent.kendall@dowjones.com