Follow drug company money in Illinois, and it leads to the psychiatry department at Rush University Medical Center, a prominent headache clinic on the North Side of Chicago, a busy suburban urology practice and a psychiatric hospital accused of overmedicating kids.

In each of these settings, doctors are drawing an extra paycheck — worth tens of thousands of dollars a year or more — for speaking to other medical professionals about pharmaceutical products at company-sponsored, company-scripted events in Illinois and across the country.