Major Depressive Disorder (MDD) is more than just the occasional period of sadness. It is when such states last for long periods of time and are out of control of the individual that is experiencing them that the diagnosis of Major Depressive Disorder can be made. Some symptoms of major depressive disorder are low mood, anhedonia, which is the loss of interest in things that one had once enjoyed, an increase in fatigue, changes in sleep or eating habits, or even thoughts that the individual feels they would be “better off dead”, and suicidal ideation.
Research has shown a strong connection between mood disorders such as MDD and history of family with the disorder, indicating a strong genetic component. Neurochemical Dysregulation is also a leading area of research that suggests a deficit in the amount of particular neurotransmitters in the brain are responsible for low mood and MDD. As the video below will explain in greater detail, the monoamine hypothesis of depression explores how neurotransmitters such as serotonin, dopamine, and norepinephrine are likely depleted in an individual with MDD. The action between neurotransmitters and receptors in the brain will be explained and how the medications used for treatment act to restore these neurotransmitters used will be presented in this video.
Reference:
McCance, K. L., & Huether, S. E. (2019). Pathophysiology: The biological basis for disease in adults and children (8th ed.). St. Louis, MO: Mosby.