Drug and Alcohol Abuse

Because they have family and genetic ties to an alcoholic, these people carry an increased risk of severe alcohol problems themselves, from two to four times that of children of nonalcoholic parents (Rutter, 2002).
When children of alcoholics reach adolescence or adulthood, they might be slightly more likely to have problems with marijuana-type drugs or with stimulants such as cocaine or amphetamines. In the fields of psychology and psychiatry, there is interest in tracing the origin of certain personality traits thought to be common among adult children of alcoholics. These traits may or may not come about because of specific alcohol-related experiences in the childhood home. They may instead stem from the general childhood environment, in which an individual was raised, additional psychiatric conditions among the parents, or general factors associated with a disordered childhood home (Rutter, 2002).
There has been steady accumulation of evidence that there is familial aggregation in alcohol abuse and dependence, which seems to be in part determined genetically. The results of more than four decades of family, twin, and adoption studies in alcoholism, although not unanimous, conjunctively provide impelling evidence that genetic influences play important roles in this and related drug abuse disorders. More specifically, 40% to 60% of the variance in heritability of alcoholism can be attributed to genetic factors (Plomin and Asbury, 2005).
Family studies which draw upon the basic design of the assessment of risk for developing the disorder in relatives of probands, who are individuals manifesting the phenotype or trait with the rates in the relatives of control groups have demonstrated that that rates of alcoholism are substantially higher in relatives of alcoholics than in relatives of nonalcoholics, with children of alcoholics demonstrating a four- to fivefold increased risk for developing the disorder. This increased risk appears to be relatively specific for alcoholism, with most family studies showing an increased rate for the disorder among relatives of alcoholic probands, while the same group does not show higher rates of other mental disorders, such as schizophrenia or bipolar disorder. Several major twin studies have directly addressed the concordance rates for alcoholism in identical versus fraternal twins. These studies have found that the concordance rate for alcoholism in male monozygotic pairs was greater than that for dizygotic twins (Stallings et al., 2005).
This led to search for a common genetic factor that might be inherited and would increase the epidemiologic risk of these disorders. Family, twin, and adoption studies indicate that genetic variation influences the risk of abuse on alcohol and nicotine. Studies on other illicit drug abuse indicate both genetic and familial contributions to the development of illicit substance use disorders. The commonly held hypothesis on substance use disorder is that common genetic risks may explain at least partly their comorbidities.
Thus these indicate that the vulnerability to abuse and addiction is at least partly determined by a genotype, the characterization would most probably be multifocal. The question remains whether these point to vulnerability to a