1. Critical role of personality and stress in drug dependency
Social inequality and social dependence are strongly involved in drug addiction. Subordinate individuals often use drugs as a means of escape from depressive feelings and stress. Stress is a risk factor for the development of drug addiction and impairment of stress adaptation may further contribute to the development and reinforcement of drug addiction. However, there is high variability of the stress response in humans: while most stress-exposed individuals display resilience, the remainder may develop drug addiction. The purpose of this study is to determine the functional genomic and hormonal fingerprint of vulnerability to stress-induced drug addiction, as a clinical prognostic tool.
In order to achieve this goal, we assess genomic and hormonal parameters potentially involved in stress-induced addiction using a unique mice model of dominance and submissiveness demonstrating vulnerability and resilience to stress respectively. We showed that these animals react differentially to cocaine and heroin, under both normal and stress-induced conditions. Moreover, we found that the stress-vulnerable submissive animals exhibit strong stress-induced drug dependency. We suggest that the highly variable vulnerability to stress-induced drug addiction seen between individuals is determined by genetic and epigenetic interplay of the Hypothalamic-Pituitary-Adrenal (HPA) axis, dopaminergic signaling and genes involved in synaptic plasticity. Data obtained in this study will be used to design personalized prognostic tools for vulnerability to drug addiction.