BUENOS AIRES  The homecoming did not go as Pablo Eche had dreamed.

After 15 months in a rehabilitation clinic battling his addiction to paco, a highly addictive drug that has laid waste to thousands of lives in this country, Mr. Eche returned to Ciudad Oculta, a poor neighborhood on the outskirts of this city.

Family members, including his mother, Bilma Acuña, an anti-paco community advocate, welcomed him back last October.

But their love was not enough. Within weeks, overcome by depression over his failure to find a job that could support his son and daughter, he once again turned to the drug for solace.

Barefoot and shirtless, his ribs poking out of his thin torso, he shuffled about in red soccer shorts in the diner with a bare concrete floor run by his family.