Family members of individuals with chronic illnesses and disabilities have increased risk of medical and mental health problems and related stress [1–3], which may affect their health care utilization . Alcohol and drug dependence, among the most prevalent chronic illnesses, have epidemiological factors and disease trajectories similar to other chronic diseases . Family members of individuals with alcohol and other drug (AOD) disorders have more medical and psychiatric conditions than fami- lies of individuals without AOD disorders, which can lead to high costs [5–8]. They also have higher costs than families of those with other chronic diseases, such as diabetes and asthma . However, only a few studies have examined whether family members’ cost changes are related to whether the AOD patient was successful in treatment [10–13].