Causes of Depression -
Biological, Endogenous or Chemical Imbalance
Depression can first occur late in life, happen acutely, and without psycho-social stresses. Because there is research suggesting a genetic/familial link to some psychiatric disorders and because medication has a high efficacy in treating some psychiatric disorders, the endogenous or biological type of depression is hypothesized to be caused by a chemical imbalance in the brain.
There are billions of neurons in the brain which interact with each other, electrically and chemically to produce cognitive, affective and behavioral capacities. Neurotransmitters, which are considered the chemical messengers, bridge the gap between the nerves and carry messages to the receiving receptor sites and neurons. Instructions are then carried out depending on the specific neurotransmitter and where it is released and utilized in the brain. The instruction can be either to continue the electrical impulse, which is called an excitatory response or to slow the impulse down, which is called an inhibitory response. The neurotransmitters; norepinephrine, dopamine, GABA, and serotonin are involved in the regulation of mood, cognition and sensory experiences (Gitlin, 1990). Because this process is complicated and has been perfectly fine tuned, any dysregulation in the way the neurons communicate, can lead to changes in mood, affect, thinking and the ability to function.
