Polymorphism in the serotonin transporter gene and response to treatment in African American cocaine and alcohol-abusing individuals

Addict Biol. 2005 Sep;10(3):261-8. doi: 10.1080/13556210500235540.

Abstract

The serotonin transporter (5-HTT) regulates serotonin transmission and modulates behavioral effects of drug of abuse. A polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) yielding a short (S) and long (L) allele has been associated with severity of substance abuse. The aims of the study were to investigate whether 5-HTTLPR genotypes differed in their response to treatment in cocaine- and alcohol-abusing patients. Polymerase chain reaction-based genotyping of a 44 base pair insertion/deletion polymorphism was performed in 141 African American cocaine-dependent patients with concurrent alcohol use who were entering a 12-week behaviorally oriented outpatient treatment program. In treatment, end of treatment and 6-month follow-up outcome measures included changes in Addiction Severity Index (ASI) scores, urine drug screens, days in treatment, individual/group sessions, dropout and completion rates. As expected, there was a reduction in substance abuse by the end of treatment and follow-up (F = 5.15, p = 0.000). However, there were no differences in the reduction in cocaine use across the LL, LS and SS genotypes. Interestingly, individuals with the S allele showed greater severity of alcohol use at admission (F = 4.84, p = 0.03), and the SS genotype showed less improvement in alcohol measures than the LL at follow-up (F = 3.68, p = 0.03), after controlling for baseline variables. While we found no association of the 5-HTTLPR variants with severity of cocaine abuse or any cocaine-related outcome measures, the data suggested that the 5-HTTLPR polymorphism may distinguish responders from non-responders to behavioral treatment in terms of alcohol use. Further investigations are required to determine the role of the 5-HTTLPR polymorphism in influencing treatment - outcome among substance abusers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Alcoholism / genetics*
  • Alcoholism / rehabilitation*
  • Alleles
  • Black or African American*
  • Cocaine-Related Disorders / genetics*
  • Cocaine-Related Disorders / rehabilitation*
  • Counseling
  • Female
  • Follow-Up Studies
  • Gene Expression Regulation / genetics
  • Genes, Reporter / genetics
  • Genotype
  • Humans
  • Male
  • Polymorphism, Genetic / genetics*
  • Promoter Regions, Genetic
  • Serotonin Plasma Membrane Transport Proteins / genetics*
  • Severity of Illness Index
  • Treatment Outcome

Substances

  • Serotonin Plasma Membrane Transport Proteins