Serum brain-derived neurotrophic factor levels in subjects with major depressive disorder with previous suicide attempt: A population-based study.

Major depressive disorders (MDD) and suicide are significant public health concerns. Recent studies have been demonstrated that alterations in Brain Derived Neurotrophic Factor (BDNF) can be associated with this psychiatric disorders, MDD and suicide. Thus, the aim of this study was to evaluate differences in serum levels in individuals with MDD and with or without suicide attempt (SA), from a population-based sample. This was a paired cross-sectional study nested in a population-based study. The psychopathology screen was performed with the Mini-International Neuropsychiatric Interview (MINI). The total population of the sample consisted of 147 subjects distributed in three groups: 49 healthy controls, 49 subjects with MDD and 49 subjects with MDD and SA (MDD + SA). The BDNF serum levels were significantly reduced in subjects with MDD and MDD + SA compared to the healthy controls. However, there were no significant differences between the MDD and MDD + SA groups with respect to BDNF serum levels. These results suggest that SA did not interfere in the serum levels of BDNF, indicating that this neurotrophin may be related to the diagnosis of MDD and not to suicide attempt.

Mental disorders, functional impairment, and nerve growth factor.

Nerve growth factor (NGF) is an important member of the neurotrophin family and its alteration has been associated with psychiatric disorders. Functionality consists of the activities that an individual can perform, as well as their social participation, which is an important factor in analyzing the carrier living conditions of subjects with psychiatric suffering. Several studies have evaluated functionality in bipolar disorder; however, no studies have evaluated the functionality in other mental disorders. There are also few studies investigating the association between functionality and the biological bases of mental disorders. This study aimed to evaluate the serum NGF levels in psychiatric patients and to verify a possible association between the serum neurotrophic levels and functionality. This was a cross-sectional study with a convenient sample obtained from the Public Mental Health Service from the south of Brazil. The final sample was composed of 286 patients enrolled from July 2013 to October 2014. Data was collected using a sociodemographic questionnaire, and the diagnosis was confirmed using the Mini International Neuropsychiatric Interview (M.I.N.I) and a Functioning Assessment Short Test. The serum NGF levels were determined using the enzyme-linked immunosorbent assay method. Statistical analyses were performed using IBM SPSS Statistic 21.0 software. NGF serum levels were increased significantly in patients with obsessive-compulsive disorder compared with patients with no obsessive-compulsive disorder (P=0.015). An increase in serum NGF levels in generalized anxiety disorder patients was observed compared with patients with no generalized anxiety disorder (P=0.047). NGF was negatively associated with autonomy (P=0.024, r=-0.136), work (P=0.040, r=-0.124), and cognition (P=0.024, r=-0.137), thereby showing that changes in serum levels of NGF are associated with functionality in mental disorders.