Are there genetic influences on addiction: evidence from family, adoption and twin studies
Article first published online: 20 MAY 2008
© 2008 The Authors. Journal compilation © 2008 Society for the Study of Addiction
Volume 103, Issue 7, pages 1069–1081, July 2008
How to Cite
Agrawal, A. and Lynskey, M. T. (2008), Are there genetic influences on addiction: evidence from family, adoption and twin studies. Addiction, 103: 1069–1081. doi: 10.1111/j.1360-0443.2008.02213.x
- Issue published online: 20 MAY 2008
- Article first published online: 20 MAY 2008
- Submitted 24 September 2007; initial review completed 24 January 2008; final version accepted 11 February 2008
Aims In this exciting era of gene discovery, we review evidence from family, adoption and twin studies that examine the genetic basis for addiction. With a focus on the classical twin design that utilizes data on monozygotic and dizygotic twins, we discuss support in favor of heritable influences on alcohol, nicotine, cannabis and other illicit drug dependence.
Methods We review whether these genetic factors also influence earlier stages (e.g. experimentation) of the addictive process and whether there are genetic influences specific to each psychoactive substance.
Results Converging evidence from these studies supports the role of moderate to high genetic influences on addiction with estimates ranging from 0.30 to 0.70. The changing role of these heritable factors as a function of gender, age and cultural characteristics is also discussed. We highlight the importance of the interplay between genes and the environment as it relates to risk for addiction and the utility of the children-of-twins design for emerging studies of gene–environment interaction is presented.
Conclusions Despite the advances being made by low-cost high-throughput whole genome association assays, we posit that information garnered from twin studies, especially extended twin designs with power to examine gene–environment interactions, will continue to form the foundation for genomic research.