Disclosed is a method of predicting a predisposition to developing an addictive disease or disorder in a test subject, said method comprising: providing a biological sample obtained from the test subject; determining whether the subject has the G allele or is homozygous for the T allele of the single nucleotide polymorphism rsl042173 of the serotonin transporter gene SLC6A4, wherein the presence of the G allele is an indication that the test subject has a lower predisposition to developing an addictive disease or disorder relative to a subject homozygous for the T allele and wherein homozygosity of the T allele in the test subject is an indication that the test subject has a higher predisposition to developing an addictive disease or disorder compared with a subject with the G allele; thereby predicting a predisposition to developing an addictive disease or disorder in a subject. Further disclosed is the use of an antagonist of the serotonin receptor 5-HT3 in the manufacture of a medicament for treating a subject with an addictive disease or disorder, wherein: (a) the use includes determining whether the serotonin transporter gene SLC6A4 of the subject has the LL genotype of functional polymorphism serotonin transporter-linked polymorphic region 5-HTTLPR, and determining whether the subject has the G allele or is homozygous for the T allele of the single nucleotide polymorphism rsl042173 of the serotonin transporter gene SLC6A4; and, (b) the antagonist of the serotonin receptor 5-HT3 is formulated for administration to a patient found to have the LL and TT genotypes so as to treat an addictive disease or disorder.
Serotonin transporter gene SLC6A4 and treatment of alcoholism