It’s often thought that addictive behaviour can be passed on through families. This phenomenon may be due to a combination of factors, including genes (heritable traits) and the social environment.
From a variety of research, including twin studies and laboratory-based genetic studies, we now know that the influences of genes and the environment are interdependent. The question of nature versus nurture has become less relevant.
What does this mean?
Well, there is no specific gene for substance use. Instead, a number of genes work together in an incredibly complex manner to influence the risk of substance use and addiction. However, the way these genes work is affected by the social environment, including drug exposure and early life stress.
From the study of epigenetics, we are beginning to learn about how genes and the environment can interact to influence a person’s patterns of drug use.
Epigenetics is concerned with the biological processes by which certain genes are ‘turned on and off’. These processes regulate the development of an organism from conception to adulthood, and regulate the organism’s responses to its environment at a cellular level.
Environmental stimuli, including drug exposure, can produce changes in the epigenetic regulation of our genes. In animal studies, these epigenetic changes have been shown to affect the way in which an animal responds to subsequent drug use opportunities. In a crude sense, repeated drug use may affect our ‘wiring’ in a way that increases the likelihood of further drug use.
The good news is that our brains are not ‘hard-wired’ but are highly adaptable – a phenomenon referred to by researchers as ‘neuroplasticity’. Certain epigenetic changes have been shown to reduce the likelihood of relapse to drug use.
These are new areas of research. We still have much to learn about the genetic and epigenetic mechanisms of substance use, and the interaction withour environment. Emerging genetic research may have implications for the development of new therapies for addiction.
The brain is flexible and adaptive to different stimuli, whether it be drug use or alternative activities. Drug use is a learned behaviour and can (with effort) be unlearned, especially in a supportive social environment.