The widely used Seroquel antipsychotic was never approved to treat post-traumatic stress disorder or the insomnia sometimes related to the afflication, but that hasn’t stopped the drug from being prescribed for that purpose by the US Department of Veteran Affairs and, in the process, becoming one of the VA’s biggest expenditures.

Since 2001, VA spending on Seroquel jumped more than 770 percent, while the number of patients covered by the VA increased just 34 percent, the Associated Press writes. Seroquel is now the VA’s second-biggest prescription drug expenditure since 2007, behind the Plavix bloodthinner. The agency spent $125.4 million last fiscal year on Seroquel, up from $14.4 million in 2001, and the growth in spending outpaces the growth in personnel who have gone through the military during that time.

Meanwile, thousands of soldiers have taken the med, and several soldiers and veterans have died, raising concerns among some military families the government is not being forthcoming about the risks, the AP writes, noting that they want Congress to investigate. The trend, by the way, is not confined to Seroquel. An investigation earlier this year found that at least one in six service members is on some form of psychiatric drug (background).

According to the VA, Seroquel is only prescribed as a third or fourth option for patients with difficult-to-treat insomnia stemming from PTSD, the AP writes. And the US Defense Department’s deputy director for force health protection, Michael Kilpatrick, tells the news service that the government has not seen any increase in dangerous side effects from Seroquel and other drugs.

But Julie Oligschlager doesn’t buy it. Two years ago, her son, Marine Cpl. Chad Oligschlaeger, 21, was being treated for PTSD when he died in his sleep at Camp Pendleton, Calif., while taking six different meds, including Seroquel, to deal with anxiety and nightmares that followed two tours of duty in Iraq. His death was attributed drug interactions, but his mom believes he died of sudden cardiac arrest caused by Seroquel. “Right now, I’m so angry, and I believe someone needs to be held accountable,” she tell the AP. “The protocol absolutely has to change.”