BDNF and schizophrenia: Despite a host of existing trials addressing the effects of pharmacological interventions (PIs) on peripheral BDNF levels in schizophrenia, while discrepant findings have been observed both in serum and plasma levels of BDNF [41,42,43,44,45,46,47,48], few studies have examined the association between NPIs and peripheral BDNF levels in patients with schizophrenia, and the results of studies have been discordant.