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Polymorphism in the serotonin transporter gene and response to treatment in African American cocaine and alcohol‐abusing individuals
Author(s) -
Mannelli Paolo,
Patkar Ashwin,
Murray Heather,
Certa Kenneth,
Peindl Kathleen,
MattilaEvenden Marja,
Berrettini Wade
Publication year - 2005
Publication title -
addiction biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.445
H-Index - 78
eISSN - 1369-1600
pISSN - 1355-6215
DOI - 10.1080/13556210500235540
Subject(s) - serotonin transporter , 5 httlpr , cocaine dependence , genotyping , genotype , substance abuse , medicine , addiction , alcohol dependence , psychiatry , polymorphism (computer science) , psychology , serotonin , alcohol , genetics , biology , gene , biochemistry , receptor
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.