“…Several studies have previously noted a low level of functioning among the SUD population in inpatient settings ( Vederhus et al, 2016b ), including compared with patients who have somatic and chronic diseases ( Donovan et al, 2005 , Miller et al, 2014 , Vederhus et al, 2016b ). A Norwegian comparative study of patients in inpatient versus IOPs found a baseline ORS score of 21.9 for the cohort as a whole, which is slightly better (approximately 2 points) than the inclusion score in the current study ( Solhaug et al, 2015 ). The mean improvement in that study at treatment end was 10.5 points for the IOP group.…”