Earlier quoted context omitted.
Lets interpret the claim charitably - people on welfare have reduced work effort, increased fertility, and increased drug consumption. Do you assert that any of those claims are false?
Drug consumption is definitely wrong. Poor people can't afford drugs. People on welfare in states that require drug testing of welfare recipients have much lower rates of drug use than the population at large. http://thinkprogress.org/economy/2015/02/26/3624447/tanf-dru...
Consider their headline number - Missouri. Testing cost $336k and found 48 drug users. Assuming welfare costs $10k/person, it saved $480k making it a net positive. All the other states they discuss had significantly higher returns (5-10x).
This all assumes not a single drug user was deterred from applying and also that not a single welfare recipient was deterred from using drugs.
Further, none of these measure the question of whether poor people do more or less drugs. Most of these programs only drug test some people and have expensive human-administered programs to decide who to test: "complete a written questionnaire about drug use" “suspicion-based drug testing for each applicant”, “reasonable suspicion exists” that they might be illegally using “a controlled substance or controlled substance analog.”
The fact that these programs found very few drug users is merely due to the fact that welfare recipients aren't dumb enough to put "yes I do drugs" on a written test.
This article is pulling the social sciences shuffle - find a socially undesirable conclusion, write an abstract hinting that it's false, and bury the truth in the data tables.