In Japan, the rehabilitation period of inpatients is divided into early-stage and late-stage. Most alcohol withdrawal symptoms are treated on an inpatient basis, after which early-stage inpatient rehabilitation is undertaken. After about 2 months of early-stage rehabilitation, patients are discharged to undergo late-stage rehabilitation treatment as outpatients. In contrast, in the European Union and United States, there is no division into early- and late-stage rehabilitation after treatment of withdrawal symptoms, and most rehabilitation is undertaken on an outpatient basis, although inpatient treatment remains an option if abstinence proves particularly difficult to achieve or if complications occur.16,32,33 Our study design reflects Japanese clinical practice, in which drug treatments to achieve maintenance of abstinence are started on the day of discharge from early-stage rehabilitation. Our study is the first to examine the efficacy of acamprosate when administration is commenced after both withdrawal symptom treatment and a period of early-stage rehabilitation have been completed. It is noteworthy that this study, based on Japanese clinical practice, has broadly similar findings to EU studies despite the different timing of drug initiation. The fact that acamprosate appears to be equally effective in different therapeutic environments shows that the drug may be used in accordance with differing patient needs and that initiating treatment at a different stage of the recovery process does not compromise its utility in maintaining abstinence. In this clinical study, the subjects received inpatient treatment before initiation of administration of the investigational drug. This inpatient treatment could have affected the prognosis after discharge.34