Major depressive disorderMajor depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introduced by a group of US clinicians in the mid-1970s, the term was adopted by the American Psychiatric Association for this symptom cluster under mood disorders in the 1980 version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), and has become widely used since.
AntidepressantAntidepressants are a class of medications used to treat major depressive disorder, anxiety disorders, chronic pain, and addiction. Common side effects of antidepressants include dry mouth, weight gain, dizziness, headaches, sexual dysfunction, and emotional blunting. There is an increased risk of suicidal thinking and behavior when taken by children, adolescents, and young adults. Discontinuation syndrome, which resembles recurrent depression in the case of the SSRI class, may occur after stopping the intake of any antidepressant, the effects of which may be permanent and irreversible.
AstrocyteAstrocytes (from Ancient Greek ἄστρον, ástron, "star" + κύτος, kútos, "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of endothelial cells that form the blood–brain barrier, provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, regulation of cerebral blood flow, and a role in the repair and scarring process of the brain and spinal cord following infection and traumatic injuries.
Glial scarA glial scar formation (gliosis) is a reactive cellular process involving astrogliosis that occurs after injury to the central nervous system. As with scarring in other organs and tissues, the glial scar is the body's mechanism to protect and begin the healing process in the nervous system. In the context of neurodegeneration, formation of the glial scar has been shown to have both beneficial and detrimental effects.
GliosisGliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, microglia, and oligodendrocytes. In its most extreme form, the proliferation associated with gliosis leads to the formation of a glial scar. The process of gliosis involves a series of cellular and molecular events that occur over several days.
AstrogliosisAstrogliosis (also known as astrocytosis or referred to as reactive astrogliosis) is an abnormal increase in the number of astrocytes due to the destruction of nearby neurons from central nervous system (CNS) trauma, infection, ischemia, stroke, autoimmune responses or neurodegenerative disease. In healthy neural tissue, astrocytes play critical roles in energy provision, regulation of blood flow, homeostasis of extracellular fluid, homeostasis of ions and transmitters, regulation of synapse function and synaptic remodeling.
Major depressive episodeA major depressive episode (MDE) is a period characterized by symptoms of major depressive disorder. Those affected primarily exhibit a depressive mood for at least two weeks or more, and a loss of interest or pleasure in everyday activities. Other symptoms can include feelings of emptiness, hopelessness, anxiety, worthlessness, guilt, irritability, changes in appetite, difficulties in concentration, difficulties remembering details, making decisions, and thoughts of suicide.
GliaGlia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. The neuroglia make up more than one half the volume of neural tissue in our body. They maintain homeostasis, form myelin in the peripheral nervous system, and provide support and protection for neurons. In the central nervous system, glial cells include oligodendrocytes, astrocytes, ependymal cells and microglia, and in the peripheral nervous system they include Schwann cells and satellite cells.
Tricyclic antidepressantTricyclic antidepressants (TCAs) are a class of medications that are used primarily as antidepressants, which is important for the management of depression. They are second-line drugs next to SSRIs. TCAs were discovered in the early 1950s and were marketed later in the decade. They are named after their chemical structure, which contains three rings of atoms. Tetracyclic antidepressants (TeCAs), which contain four rings of atoms, are a closely related group of antidepressant compounds.
Antidepressant discontinuation syndromeAntidepressant discontinuation syndrome, also called antidepressant withdrawal syndrome, is a condition that can occur following the interruption, reduction, or discontinuation of antidepressant medication following its continuous use of at least a month. The symptoms may include flu-like symptoms, trouble sleeping, nausea, poor balance, sensory changes, akathisia, intrusive thoughts, depersonalization and derealization, mania, anxiety, and depression. The problem usually begins within three days and may last for several weeks or months.
