The three programs in addiction treatment are inpatient programs, partial hospitalization programs (PHP), and intensive outpatient programs (IOP). The main differences are in the number of programs a patient will experience and whether they will stay on-site (as with inpatient) or return home nightly (as in PHP and IOP). Inpatient treatment can be six days a week, PHP is typically five days a week, and IOP is typically several hours at a time, three days or evenings weekly.