The development of opioid dependence involves the interaction of social-behavioural, physiological, genetic and environmental influences. Certain genetic polymorphisms in the immune and neurological pathways are found in higher proportions in the drug dependent population compared with the healthy population. However, the functional consequences of these genetic polymorphisms on the human physiological response to addictive drugs like opioids remain unclear.

Stress response is mediated through the hypothalamic-pituitary-adrenal axis and influences immune function. Moreover, stress is known to increase the risk of drug dependence through positive and negative reinforcement. It is hypothesized that genetic variation of neuroimmune markers, such as interleukin(IL)-1β gene, will influence peripheral stress markers in response to the administration of an addictive drug.

This study evaluates the phenotypic effects of these genetic variations. Specifically, a single dose of an addictive drug (oxycodone) is administered to healthy individuals and a number of physiological, immunological and neurological responses are assessed. These measures are then associated with variation in the IL-1B gene. Results of this work suggest a genetic difference in stress response to drug administration.