When the drugs came, they hit all at once. It was the 80s, and by the time one in 10 people had slipped into the depths of heroin use -bankers, university students, carpenters, socialites, miners - Portugal was in a state of panic. Álvaro Pereira was working as a family doctor in Olhão in southern Portugal. "People were injecting themselves in the street, in public squares, in gardens," he told me. "At that time, not a day passed when there wasn't a robbery at a local business, or a mugging."