And many experts say that as the government has cracked down on cartels, they have splintered, generating more dealers, especially at lower levels. Often those dealers are paid not in dollars but in drugs, says Haydee Rosovsky, the former head of Mexico's commission on addiction.
More availability means cheaper drugs. These days the price of a gram of cocaine is between 150 and 200 pesos ($11 to $15), says Benjamin Garcia, who works at Monte Fenix, while crack is a tenth of that. In the early 1990s, the price of cocaine was nearly three times as expensive.
"You can get it anywhere," says Flores, who, as a junior high student, had a network of friends from whom he could buy drugs.
Cocaine use has steadily increased over the past decade, while crack use has exploded in the past few years. Methanphetamine consumption is a growing public health concern, too, particularly in the border towns of Ciudad Juárez and Tijuana, says Ricardo Sanchez, who heads the research department for a network of 110 government clinics that treat addiction.
The percentage of those who have tried drugs at least once in their life rose from just over 5 percent in 2002 to 6 percent last year, or by 1 million users. Each year they are younger, says Mr. Sanchez.