Pharmacogenomics and addiction to opiates.

Area of Science:

• Neuroscience
• Genetics
• Pharmacology

Background:

• Opiate abuse and dependence have a substantial genetic component, separate from other substance use disorders.
• Previous pharmacogenetic studies focused on candidate genes, yielding limited and unreproducible findings.
• Replication of initial genetic association findings in opiate addiction has been problematic.

Purpose of the Study:

• To review the current state of pharmacogenomic and pharmacogenetic research in opiate addiction.
• To highlight the limitations of candidate gene approaches and the potential of genome-wide strategies.
• To discuss the application of unbiased, genome-wide searches for genetic risk factors in opiate addiction.

Main Methods:

• Review of existing pharmacogenetic and pharmacogenomic studies in animals and humans concerning opiate addiction.
• Analysis of candidate gene association studies and their replication issues.
• Evaluation of genome-wide approaches like quantitative trait loci (QTL) mapping and differential gene expression studies.

Main Results:

• Candidate gene studies for opioid addiction have shown inconsistent and difficult-to-replicate results.
• Genome-wide approaches, such as QTL mapping in rodents and microarray-based expression studies, are better suited for unbiased risk gene discovery.
• Few studies currently meet the requirements of a true pharmacogenomic approach for opiate addiction.

Conclusions:

• The genetic transmission of opiate addiction risk is significant and distinct.
• Unbiased, genome-wide pharmacogenomic studies are essential for identifying reliable genetic risk factors for opiate addiction.
• Further research employing advanced genomic technologies is needed to understand the genetic basis of opioid dependence.