Genetic Epidemiology of Alcoholism

This three-year project aims to: 1) search for susceptibility genes for alcoholism other than known alcohol-metabolizing genes; 2) identify environmental risk factors of alcohol dependence for subjects with known risk genotypes; 3) elucidate the interaction among candidate genes and between genes and environment. The original design included three branches: 1) affected sib-pair families (n=200); 2) primary alcoholics (n=100) and nonalcoholic controls (n=100)l and 3) adolescent sons of primary alcoholics (n=100) and nonalcoholic controls (n=100). The phenotypes to be investigated in all three branches include both qualitative (diagnostic categories) and quantitative traits, alcohol drinking quantity and frequency, and scores on several personality scales). We have completed the development of valid and reliable psychometric instruments with cross-cultural comparability for assessing potential phenotypes (e.g., the Chinese version of the Tridimensional Personality Questionnaire, the Brown-Goodwin Aggression Inventory, and the Yale-Brown Obsessive Compulsive Scale for heavy drinking) and the set-up of High Performance Liquid Chromatography. We have trained participating psychiatrists to conduct clinical interview using the Chinese Schedule for Clinical Assessment in Neuropsychiatry (SCAN), and trained research assistants to conduct psychometric measurements and recruitment protocol. With regard to case finding, we have difficulty in getting the other non-hospitalized affected sib, who usually lacked insight, to participate in the study. To surpass this bottleneck in our data collection, we now collect cases not limited to affected sibpairs. The affected (for association study) and trios (i.e., one affected sib plus two parents, which can be used in transmission/disequilibrium test) from any identified alcohol dependent cases are recruited for the project. If a family contains affected sib-pairs, then every effort will be paid to collect such ‘quartet” for affected sib-pair analysis. So far, we have identified 81 families with both solo and trio and doing both assessment and DNA preparation. Only 9 of these families have quartet. Another 81 normal controls have been collected from health screening population with both DNA and assessment completed.