Substance use disorder (SUD) is the persistent use of drugs (including alcohol) despite substantial harm and adverse consequences. SUDs are characterised by an array of mental, emotional, physical, and behavioural problems such as chronic guilt, an inability to reduce or stop consuming the substance(s) despite repeated attempts, driving while intoxicated, and physical and physiological withdrawal symptoms.
SUDs are among the most common and prevalent mental health disorders and are accompanied by a range of psychosocial and medical dysfunctions and substantially increased mortality. A study on the mental health of Australians has shown that 1 in 20 Australians aged 16-85 years (5.1%) had a substance use disorder in the last 12 months.1 Alcohol Use Disorder was the most common form of SUD with a prevalence of 2.9%.
SUDs have been shown to be inherited within families and a series of twin and adoption studies have confirmed that genetic risk factors contribute substantially to individual differences in the risk for developing an SUD.
Gambling Disorder (GD) is a behavioural addiction characterised by persistent and recurrent problematic gambling behaviour leading to significant impairment and distress. Similar to SUDs, individuals with lifetime experience of GD have a preoccupation with gambling, have unsuccessful attempts to control or stop gambling, gamble with increasing amounts of money, ‘chase’ losses, and often experience the loss of a relationship, job, or educational opportunity because of their gambling. Other addictive behaviours include Gaming Disorder (GD) or Internet Gaming Disorder (IGD) which are characterised by persistent or recurrent gaming behaviour (‘video-gaming’), which may be online or offline.
There is an urgent need for the development of more effective interventions and improved understanding of the biological mechanisms underlying the risk of SUDs and addictive behaviours. Genome-wide association studies (GWAS) have identified hundreds of genomic regions that contain genetic risk variants (or single nucleotide polymorphisms) robustly associated with substance use traits, including, for example, alcohol use and Alcohol Use Disorder, tobacco smoking, and cannabis use. Although increasingly large GWAS meta-analyses are improving our ability to discover genes and genetic variants, elucidating the underlying molecular processes remains elusive.
Unlike SUDs, there are larger knowledge gaps that exist in addictive behaviour research and large-scale genetic studies are pivotal to address them. Currently, the genetic architecture underlying GD and GD/IGD is not well understood; few candidate gene studies and GWAS have been published.
We aim to identify genetic risk factors for substance use, SUDs, and other addictive behaviours. We are currently conducting, or planning to conduct, genetic studies that will provide a better understanding of the biological mechanisms underlying these disorders and behaviours. This will provide important information to develop more effective intervention and treatment strategies.