Serum BDNF levels and cocaine-induced transient psychotic symptoms

Background: Cocaine-induced psychosis (CIP) is among the most serious adverse effects of cocaine. Reduced serum BDNF levels have been reported in schizophrenia and psychosis; however, studies assessing the involvement of BDNF in CIP are lacking. Methods: Twenty-two cocaine-dependent patients (ages 33.65 ± 6.85) who had never experienced psychotic symptoms under the influence of cocaine (non-CIP) and eighteen patients (ages 34.18 ± 8.54) with a history of CIP completed a two-week detoxification program in an inpatient facility. Two serum samples were collected from each patient at baseline and at the end of the protocol. Demographic, consumption and clinical data were recorded for all patients. A paired group of healthy controls was also included. Results: At the beginning of the detoxification treatment, serum BDNF levels were similar in the non-CIP and the CIP groups. During early abstinence, the non-CIP group exhibited a significant increase in serum BDNF levels (p=0.030), whereas the CIP group exhibited a decrease in serum BDNF levels. Improvements in depression (BDI, p = 0.003) and withdrawal symptoms (CSSA, p=0.013) show a significant positive correlation with serum BDNF levels in the non-CIP group, whereas no correlation between the same variables was found in the CIP group. Conclusions: This study suggests that BDNF plays a role in the transient psychotic symptoms associated with cocaine consumption. In the non-CIP group, the increase in serum BDNF appears to be driven by the effects of chronic cocaine consumption and withdrawal. In contrast, patients with CIP share some of the neurotrophic deficiencies that characterize schizophrenia and psychosis.