Many studies with rodent models have illustrated the role of genetic factors in determining the severity of ethanol withdrawal. In studies using inbred mouse strains and mice selectively bred for drug sensitivity, a consistent finding has been that genotypes susceptible to alcohol withdrawal are also susceptible to withdrawal from other drugs with CNS depressant effects. A new method for rough genetic mapping of genes associated with withdrawal, quantitative trait loci (QTL) gene mapping, has recently been employed in the BXD RI recombinant inbred mouse series. Several QTLs are associated with alcohol withdrawal: One such QTL on Chromosome 1 is described. An area of Chromosome 2 contains a QTL marker for a gene affecting withdrawal from acute and chronic ethanol, nitrous oxide, and high-pressure neurological syndrome Type I clonic convulsions.