Genetic variations always interact with environmental factors in pathogenesis. The important role of the dopamine receptor A1 allele in alcoholism is demonstrated through its interaction with stress, rule setting and treatment.
Stress increases the probability of alcoholism and the dopamine receptor A1 allele makes this more likely.

A Risk Allele of the Dopamine Receptor Gene (DRD2 A1) Interacts with Negative Life Event Stress and Occupational/Economic Stress to Increase the Probability of Alcoholism

Stress is a known risk factor for alcoholism and these findings show that genetic factors interacting with stress can lead to alcoholism.A. 115 Adult male Brazilian Caucasian alcoholics hospitalized for detoxification were interviewed using the semi structured assessment for the genetics of alcoholism scale and physiologic dependence symptoms were scored (mean = 8, range 0 - 15). A life experiences survey was used to assess the impact of negative life events in the past year.(Constructed from data in Bau, C.H.D. et al. A J Med Genet (Neuropsy genetics), 92: 302 - 306, 2000)B. 304 Adult Honduran males of Mayan descent were studied with an epidemiological design and were administered the MAST scale (21% scored in the alcoholic range, 10% in the high risk range and 65% in the nonalcoholic range). The Hispanic Stress Inventory was used to measure occupational/economic stress. (Constructed from data in Madrid, G.P. et al. Alcohol, 23: 117 - 122, 2001)©2010 NBEP
Low parental rule setting increases alcohol use in adolescents and this is most evident in individuals with the dopamine receptor A1 allele

The DRD2 Risk Allele (DRD2-A1) Increases Alcohol Use in Adolescents with Low Parental Rule-Setting

Parental rule setting on alcohol use was assessed in 165 male and female non regular drinking adolescents at age 14.4 years and alcohol use was assessed 1 year later. Overall high parental rule-setting on alcohol use was significantly related to low alcohol use but DRD2 genotype did not relate to alcohol drinking except for the interaction with parental rule setting. Controlling for general parental behavioral control did not alter the results. (Constructed from data in vander Zwaluw, C.S. et al. Molecular Psychiatry, 15: 727-735, 2010) ©2010 NBEP
Individuals with the dopamine receptor A1 allele are more responsive to treatment with a dopamine agonist, suggesting that the decreased sensitivity in individuals with the A1 allele is normalized with agonist treatment.

The Dopamine Agonist Bromocriptine Preferentially decreases craving in Alcoholic Subjects with the TaqlA, Allele of the Dopamine D2 receptor

From 83 Caucasian alcoholic inpatients, 52 were initially assigned to bromocriptine treatment and 31 to placebo, mean age 44 yrs, 93% male. Craving assessed on the Borg craving scale at 0, 3 and 6 weeks of inpatient treatment. Craving did not differ at 3 weeks of treatment but did differ at 6 weeks treatment.(Constructed from data in Lawford, B.R. et al. Nature Med, 1: 337, 1995)©2006 NBEP