Neurotrophic factors play an important role in both neurogenesis and neuronal plasticity. Today, it is known that the levels of neurotrophic factors alter in neuropsychiatric disorders such as major depressive disorder (MDD), schizophrenia, Alzheimer's disease or Parkinson's disease. In recent years, some studies demonstrated that MDD may occur as a result of the changes in neuronal plasticity at structural and molecular levels. Many studies demonstrated reduced levels of brain-derived neurotrophic factor (BDNF) in patients with MDD and increased levels of serum BDNF following an adequate antidepressant treatment or ECT. Many studies involving patients with schizophrenia found alterations in serum levels of BDNF.
Some of the studies reported no significant differences in serum levels of BDNF between patients and normal controls some reported decreased serum levels of BDNF in treated or first-episode schizophrenic patients. Epidermal growth factor (EGF) is a well-known neurotrophic factor that involve in neuronal growth and synaptic plasticity. Several studies reported the relationship between EGF levels and neuropsychiatric disorders such as schizophrenia, autism and Parkinson's disease. Although, the EGF association has been reported in aforementioned neuropsychiatric disorders, it has not been well documented with MDD. Tian et al. are the first to demonstrate that the plasma EGF levels in patients with MDD were significantly lower than those in the control participants. They also concluded that the EGF levels may be used as biomarkers for the early diagnosis and prognosis of psychiatric disorders.
The BDNF association has been well documented with MDD or schizophrenia. However, to the best of our knowledge, the EGF association with psychiatric disorders particularly with schizophrenia has not been studied extensively.
Related cited articles: Schizophrenia Research and Treatment