The primary objective is to directly compare the efficacy of acamprosate, naltrexone and placebo for relapse prevention in alcoholics.

The primary objective is to directly compare the efficacy of acamprosate, naltrexone and placebo for relapse prevention in alcoholics. The secondary objective is to establish an association between patients' motivational type and drug effects. The aim is to improve alcoholism treatment by identifying characteristics for response to specific pharmacological relapse prevention. Such items could allow for an individually adapted pharmacotherapy of alcoholism. Specifically, we will study the possible dependence of the efficacy of naltrexone and/or acamprosate on different motivational types (reward versus relief craving) and genetic profiles referring to glutamatergic and opioidergic candidate genes. Lastly, the longterm costs and cost-effectiveness of the different treatment strategies for alcoholics chosen in our study are established.

Inclusion Criteria:

1. Participants will have a current DSM-IV/ICD 10 diagnosis of alcohol dependence.
2. Participants must have had a minimum of 14 drinks (females) or 21 drinks (males) on average per week over a consecutive 30-day period in the 90-day period prior to initiation of abstinence, and must have had two or more days of heavy drinking (defined as 4 drinks for females and 5 drinks for males) in the 90-day period prior to initiation of abstinence.
3. Participants must have had a minimum of 72 hours of abstinence and no significant withdrawal symptoms (CIWA < 8) prior to randomization.
4. At least 2 weeks of inpatient treatment.
5. Participants can be abstinent for a maximum of 28 days prior to randomization.
6. Participants are willing not to seek additional psychotherapy during the first 6 months of study except attendance of mutual help groups.
7. Participants have to sign a witnessed declaration of informed consent.

Exclusion Criteria:

1. Participants who meet current DSM-IV criteria for bipolar disorder, schizophrenia, bulimia/anorexia, dementia, or a psychological disorder for whom medication is indicated, but no other Axis I disorders that are not medicated and are not severe enough to require medications.
2. Participants who require psychopharmacotherapy.
3. Participants who require therapy with any medications which pose safety issues.
4. Participants with a current abuse of any psychoactive drug and who show a positive drug test on an urine screen.
5. Participants with a lifetime diagnosis of dependence on any psycho-active drug except for nicotine or habitual caffeine use.
6. Participants who have significant medical disorders which would increase the potential risk of the study treatment or interfere with the study participation.
7. Participants with abnormal AST or ALT (more than 5 times the normal level).
8. Participants who are pregnant or nursing infant(s).
9. Women during childbearing years without an effective contraceptive method.
10. Participants developing sensitivity to the study medication.
11. Participants who are illiterate or are unable to read and write German.