Individual differences underlying susceptibility to addiction: Role for the endogenous oxytocin system

Abstract

Recent research shows that the effects of oxytocin are more diverse than initially thought and that in some cases oxytocin can directly influence the response to drugs and alcohol. Large individual differences in basal oxytocin levels and reactivity of the oxytocin system exist. This paper will review the literature to explore how individual differences in the oxytocin system arise and examine the hypothesis that this may mediate some of the individual differences in susceptibility to addiction and relapse. Differences in the oxytocin system can be based on individual factors, e.g. genetic variation especially in the oxytocin receptor, age or gender, or be the result of early environmental influences such as social experiences, stress or trauma. The paper addresses the factors that cause individual differences in the oxytocin system and the environmental factors that have been identified to induce long-term changes in the developing oxytocin system during different life phases. Individual differences in the oxytocin system can influence effects of drugs and alcohol directly or indirectly. The oxytocin system has bidirectional interactions with the stress-axis, autonomic nervous system, neurotransmitter systems (e.g. dopamine, serotonin and GABA/glutamate) and the immune system. These systems are all important, even vital, in different phases of addiction. It is suggested that early life adversity can change the development of the oxytocin system and the way it modulates other systems. This in turn could minimise the negative feedback loops that would normally exist. Individuals may show only minor differences in behaviour and function unless subsequent stressors or drug use challenges the system. It is postulated that at that time individual differences in oxytocin levels, reactivity of the system or interactions with other systems can influence general resilience, drug effects and the susceptibility to develop problematic drug and alcohol use.

Oxytocin prevents ethanol actions at δ subunit-containing GABA A receptors and attenuates ethanol-induced motor impairment in rats

“…This finding comes at a time when there is substantial interest in the potential of OT as a therapeutic for various psychiatric problems (18), including substance-use disorders (19)(20)(21)(22)(23). A robust antagonistic action of OT on moderate doses of ethanol was evident in the present report at both the behavioral and cellular level of analysis.…”

Early Social Environment Affects the Endogenous Oxytocin System: A Review and Future Directions

“…More recent data demonstrate the pro-social role of oxytocin, including its role in social and emotional regulation (6), orgasm (7), regulating stress, and anxiety and facilitation of pair, maternal and infant bonding (8–12). Interestingly, the release of oxytocin is dependent on the social context.…”

The Effects of Oxytocin on Withdrawal, Craving and Stress Response in Heroin-Dependent Patients: A Randomized, Double-Blind Clinical Trial

“…Recent studies indicate that social attachments protect against addiction and health consequences of stress, whereas drug abuse and chronic stress can undermine social attachment [29,30]. Indeed, negative social experiences generally increase the vulnerability to drug abuse, while the development of strong social attachments, including parent-offspring and adult pair bonding may buffer substance abuse [31].…”