Alcohol dependence is one of the psychiatric disorders for which hereditary influence is strongest. In fact, the importance of genetic factors in transmission of vulnerability to alcohol dependence was first described in literature many years ago by psychiatrists who dedicate to its study. That vulnerability may be explained by an epigenetic model in which biological hereditary factors associate with environmental factors to cause alcohol dependence.

Study the influence of genetic factors on alcohol dependence.

During 4 consecutive months a sample of alcoholic patients was collected from the Alcohol Treatment Unit of CHPL (inpatients and outpatients). Biographic data, patient's psychiatric diagnosis and family history of alcohol dependence or of dependence of other drugs were recorded.

Initial sample included 122 patients. After exclusion of patients who were also hospitalized in that period, the final sample included 102 patients (26% female), with a mean age of 48 years old. Main patients’ diagnosis was alcohol dependence but most of them (52%) presented psychiatric comorbidity. Most patients (55%) had family history of alcohol dependence or dependence of other substances, 26% did not have and 19% did not know. For 61% of patients, the father and/or mother were the affected relative. Most patients (61%) who had a family history of alcohol dependence or dependence of other substances had 2 or more affected relatives.

Most patients with alcohol dependence have family history of alcohol dependence or dependence of other substances, usually in more than 1 relative, which must be taken in account during treatment.

The authors have not supplied their declaration of competing interest.