In recent years, the term 'chronic alcoholism' has had a meaning that is more descriptive than diagnostic. Several subtypes of alcoholism have been established and are now a necessary tool for studying therapy outcome. Alcohol-dependent patients can be subtyped based on clearly assigned dimensions (e.g. biological, sociological and psychological disturbances). Craving and the underlying disturbance must be treated. The number of pharmacological agents that may reduce alcohol intake has increased recently. We conducted a prospective long-term study based on four subtypes of alcohol-dependent patients to assess the efficacy of acamprosate. Our findings demonstrate that these patient subtypes are relevant to outcome in trials of pharmacological agents. We strongly recommend subtyping alcohol-dependent subjects in future trials, because the usefulness of effective drugs could be overlooked when they are tested in a heterogeneous population.