Andrew White returned from a nine-month tour in Iraq beset with signs of post-traumatic stress disorder: insomnia, nightmares, constant restlessness. Doctors tried to ease his symptoms using three psychiatric drugs, including a potent anti-psychotic called Seroquel. Thousands of soldiers suffering from PTSD have received the same medication over the last nine years, helping to make Seroquel one of the Veteran Affairs Department’s top drug expenditures and the No. 5 best-selling drug in the nation.