The relationship between alcoholism and neurosis: evidence from a twin study

The twin register of the Maudsley Hospital was used to select a series of monozygotic (MZ) and same-sexed dizygotic (DZ) twins who had been given an ICD8 diagnosis related to alcoholism. They and their co-twins were traced. Medical and drinking histories were compiled (from records and by interview) for 56 twin-pairs, to permit current and retrospective diagnosis of any neurotic disorders. RDC diagnoses of panic disorder, generalised anxiety disorder, obsessive-compulsive disorder and phobias were more common in the alcoholic probands and the co-twins who were also alcoholics than in the normal-drinking co-twins. The Eysenck Personality Questionnaire (EPQ) and the Severity of Alcohol Dependence Questionnaire (SADQ) were completed by 54 individuals. Neuroticism scores were significantly higher for both male and female alcoholics than for their normal-drinking co-twins; and intra-pair differences in neuroticism were significantly correlated with intra-pair differences in severity of dependence. These results suggest that both clinically diagnosed neurotic illness and high neuroticism scores are more often a consequence than a cause of alcoholism.