Circulating ghrelin changes as a biomarker of the stress response and craving in abstinent smokers

RATIONALE: There has been growing interest in the role of ghrelin in stress and addiction. Ghrelin regulates central reward mechanisms by mediating the mesolimbic dopaminergic system. Stress also induces neurophysiological activations related to drug reward. However, the extent to which psychosocial stress is associated with changes in ghrelin levels has not been tested in individuals with nicotine dependency undergoing withdrawal, a condition known to induce stress-like symptoms.

OBJECTIVES: We investigated the association of stress-induced ghrelin, craving, and smoking lapse.

METHODS: Thirty-six smokers attended a laboratory session that included acute stress tasks during the initial phase of quitting. Self-report measures and biochemical samples were collected for the assessment of smoking status. Blood samples for the measurement of ghrelin and self-report measures of craving were collected multiple times throughout the session RESULTS: Multivariate analysis of variance controlling for gender found a significant main effect of sampling time and lapse group (p < 0.05). Ghrelin levels significantly increased over the pre-stress and post-stress periods (ps < 0.001), suggesting a delayed stress response. Those who lapsed during the study had higher ghrelin levels than those who were able to successfully abstain. A ghrelin stress response was calculated and a significant association was found between this response and craving, which changed across time points (ps < 0.008).

CONCLUSIONS: The results of this study demonstrate that ghrelin is sensitive to acute manipulation of stress and that there is potential usefulness for ghrelin as a marker of stress, craving, and smoking lapse.