In recent decades, traumatic brain injury (TBI) has become one of the most important health problems worldwide and is a major cause of morbidity, mortality and economic losses. Mild traumatic brain injury (mTBI) is less considered, with clinical underestimation leading to an epidemiological underevaluation of its incidence. Many of the signs and symptoms induced by mTBI are difficult to highlight clinically, especially those related to cognitive, behavioral, or emotional impairment. The complexity of the biological mechanisms induced by mTBI in the elderly determines synchronous pathogenic actions in which the vascular, inflammatory and neurodegenerative elements are intertwined. It is difficult to highlight a major pathogenic factor, since they act simultaneously, multimodally, in a real pathogenic cascade. The identification of mTBI and cerebral vascular changes by neuroimaging techniques, transcranial Doppler (TCD) or biological markers, suggests a potential prophylactic intervention by using neuroprotective factors as early as possible. Proper prophylaxis measures with neurotrophic treatment, rebalancing the gamma-aminobutyric acid (GABA)/glutamate balance and combating the chronic inflammatory process, can become important pharmacological therapeutic targets.

The present review addresses major depressive disorder (MDD) and the implications of antidepressant treatment in the field of brain neuroplasticity, an effect initially considered adjacent but currently passed as central in the process of remission of MDD. Both in experimental animal studies and in human studies in subjects with mood disorders, neuroplasticity is considered the fundamental mechanism of neural defense against stress. Stress is the mediator between neurofunctional, neuroendocrine, neurobiological and neuroimmune disorders and depressive pathology of various intensities. Neurons have a high potential to adapt to the influences of internal and external factors. We are talking about neuroplasticity at different levels: structural neuroplasticity involving adult neurogenesis (such as plastic changes, dendritic reconstruction, when the morphology of the spine is affected); synaptic functional neuroplasticity and molecular and cellular mechanisms involved. These two major dimensions explain the pathophysiology of depression, as well as the convergence of the mechanisms involved in stress, major depressive decompensations, and the concept of neuroplasticity as the present target for new effective and potent antidepressant treatments.

The article is a review of the latest meta-analyses regarding the genetic spectrum in schizophrenia, discussing the risks given by the disruptedin-schizophrenia 1 (DISC1), catechol-O-methyltransferase (COMT), monoamine oxidases-A/B (MAO-A/B), glutamic acid decarboxylase 67 (GAD67) and neuregulin 1 (NRG1) genes, and dysbindin-1 protein. The DISC1 polymorphism significantly increases the risk of schizophrenia, as well injuries from the prefrontal cortex that affect connectivity. NRG1 is one of the most important proteins involved. Its polymorphism is associated with the reduction of areas in the corpus callosum, right uncinate, inferior lateral fronto-occipital fascicle, right external capsule, fornix, right optic tract, gyrus. NRG1 and the ErbB4 receptor (tyrosine kinase receptor) are closely related to the N-methyl-D-aspartate receptor (NMDAR) (glutamate receptor). COMT is located on chromosome 22 and together with interleukin-10 (IL-10) have an anti-inflammatory and immunosuppressive function that influences the dopaminergic system. MAO gene methylation has been associated with mental disorders. MAO-A is a risk gene in the onset of schizophrenia, more precisely a certain type of single-nucleotide polymorphism (SNP), at the gene level, is associated with schizophrenia. In schizophrenia, we find deficits of the γ-aminobutyric acid (GABA)ergic neurotransmitter, the dysfunctions being found predominantly at the level of the substantia nigra. In schizophrenia, missing an allele at GAD67, caused by a SNP, has been correlated with decreases in parvalbumin (PV), somatostatin receptor (SSR), and GAD ribonucleic acid (RNA). Resulting in the inability to mature PV and SSR neurons, which has been associated with hyperactivity.