Two years ago, on a gray January afternoon, I visited the Ridge Avenue homeless shelter in Philadelphia. I was looking for poor people who had been paid to test experimental drugs. The streets outside the shelter were lined with ruined buildings and razor wire, and a pit bull barked behind a chain-link fence. A young guy was slumped on the curb, glassy-eyed and shaky. My guide, a local mental health activist named Connie Schuster, asked the guy if he was okay, but he didn't answer. "My guess is heroin," she said.
We arrived at the shelter, where a security guard was patting down residents for weapons. It didn't take long for the shelter employees to confirm that some of the people living there were taking part in research studies. They said that the studies are advertised in local newspapers, and that recruiters visit the shelter. "They'll give you a sheet this big filled with pills," a resident in the shelter's day room told me the next day, holding up a large notebook. He had volunteered for two studies. He pointed out a stack of business cards on a desk next to us; they had been left by a local study recruiter. As we spoke, I noticed that an ad for a study of a new ADHD drug was running on a television across the room.
If you're looking for poor people who have been paid to test experimental drugs, Philadelphia is a good place to start. The city is home to five medical schools, and pharmaceutical and drug-testing companies line a corridor that stretches northeast into New Jersey. It also has one of the most visible homeless populations in the country. In Philly, homeless people seem to be everywhere: sleeping in Love Park, slumped on benches in Suburban Station, or gathered along the Benjamin Franklin Parkway, waiting for the free meals that a local church gives out on Saturdays.