Doctors in Indiana overwhelmingly prescribe controlled substances for pain and other symptoms but infrequently use an electronic system designed to detect prescription drug abuse, a study released Monday found. The findings presented to the state Board of Pharmacy by Indiana University's Center for Health Policy show that nearly 90 percent of Indiana's doctors and dentists said they had prescribed controlled substances within the past year. And while most doctors said they used the INSPECT drug tracking system, only about 20 percent said they had used it within the past month. Many said they simply didn't have time to check the system every day.