Changes in brain-derived neurotrophic factor (BDNF) during abstinence could be associated with relapse in cocaine-dependent patients

Brain-derived neurotrophic factor (BDNF) is involved in cocaine craving in humans and drug seeking in rodents. Based on this, the aim of this study was to explore the possible role of serum BDNF in cocaine relapse in abstinent addicts. Forty cocaine dependent subjects (DSM-IV criteria) were included in an inpatient 2 weeks abstinence program. Organic and psychiatric co-morbidities were excluded. Two serum samples were collected for each subject at baseline and at after 14 abstinence days. After discharge, all cocaine addicts underwent a 22 weeks follow-up, after which they were classified into early relapsers (ER) (resumed during the first 14 days after discharge,) or late relapsers (LR) (resumed beyond 14 days after discharge). The only clinical differences between groups were the number of consumption days during the last month before detoxification. Serum BDNF levels increased significantly across the 12 days of abstinence in the LR group (p=0.02), whereas in the ER group BDNF remained unchanged. In the ER group, the change of serum BDNF during abstinence negatively correlated with the improvement in depressive symptoms (p=0.02). These results suggest that BDNF has a role in relapse to cocaine consumption in abstinent addicts, although the underlying neurobiological mechanisms remain to be clarified.