A study of for-profit addiction treatment programs finds many of them charge inflated fees and use misleading sales practices to attract patients, NPR reports.

Researchers at Yale University conducted an audit survey of 613 residential programs nationally, posing as uninsured cash-paying individuals using heroin and seeking addiction treatment. They found people who answered phones at for-profit treatment programs typically were salespeople who did not ask any medical questions.

One-third of callers were offered admission before clinical evaluation, usually within one day, the researchers reported in the journal Health Affairs. Most programs required up-front payments, with for-profit programs charging more than twice as much ($17,434) as nonprofits ($5,712).

“We actually found less than a third of the programs offered medication maintenance treatment, which is the gold standard of treatment,” lead researcher Tamara Beetham told NPR.