Long-term effects of antipsychotics on serum BDNF levels in patients with schizophrenia

Brain-derived neurotrophic factor (BDNF) is implicated in the etiology of schizophrenia, and peripheral BDNF levels are affected by the short-term antipsychotic treatment. However, the data on their long-term effects on BDNF levels are scarce, and there is no information whether BDNF levels change during sustained remission in relation to values in healthy individuals. The aim of the present study was to compare serum BDNF levels in patients in long-term remission and healthy controls. This study is an extension of our previous research on the effects of olanzapine and risperidone on serum BDNF in acute-episode patients with schizophrenia. Patients who remained in remission for at least 3 years on the same antipsychotic regimen (40 % of the initial cohort) were included. Symptoms were assessed by the Positive and Negative Syndrome Scale (PANSS). Serum BDNF levels were measured by ELISA in patients in remission (N = 20), evaluated at baseline, after 6 weeks of treatment and after 3 years of treatment, and in healthy individuals (N = 40). At baseline (p = 0.046) and after 6 weeks of treatment (p = 0.028), patients had significantly lower BDNF levels than controls. However, after 3 years of continuous antipsychotic maintenance treatment, serum BDNF levels were increased compared to baseline and values after 6 weeks of treatment in remitted patients, and were also significantly higher in patients than in healthy controls (p = 0.002). Antipsychotic medications appear to have distinct effects on serum BDNF levels in short-and long-term treatment. It remains to be determined if such finding may be related to potential neuroprotective effects of antipsychotic maintenance treatment.