Onset of depression more complex than a brain chemical imbalance Updated: April 11, Published: Rather, there are many possible causes of depression, including faulty mood regulation by the brain, genetic vulnerability, stressful life events, medications, and medical problems. To be sure, chemicals are involved in this process, but it is not a simple matter of one chemical being too low and another too high.
A literal ton of research has been done on the causes of depression. Below is a brief discussion of the multiple biological, psychological and social factors that have been identified as being related to the development of depression. In context of the Diathesis-Stress hypothesis, the biological factors typically function as diatheses, the psychological factors may serve as diatheses or stressors, and sociological factors tend to function as stressors or triggers.
Biology of Depression You may have heard that depression is the result of a simple imbalance of brain chemicals. Although brain chemicals are certainly part of the cause, this explanation is too simplistic.
Even just considering the biological dimension of depression, the brain has multiple layers of complexity.
Neurochemistry Neurotransmitters The brain uses a number of chemicals as messengers to communicate with other parts of itself and with the nervous system. Neurons are constantly communicating with each other by way of exchanging neurotransmitters. A tiny space called a synapse connects neurons to one another.
In a simple scenario, one neuron the sender sends a neurotransmitter message across the synapse and the next neuron the receiver receives that message by way of a receptor embedded on its surface.
Receptors are tiny molecules that function like a lock on a door. Receptors have chemical channels with particular shapes, which perfectly match the shape of neurotransmitter molecules that are sent across the synapse.
As a result, the receptor becomes activated or opened, just like when a key enters a lock and turns to open it.
When there are no neurotransmitter molecules around to unlock the receptors, the receptors remain in a closed or inactive state. There needs to be some quiet time between neurotransmitter messages for those messages to have any meaning.
It is important that receptors be allowed to reset and deactivate between messages so that they can become ready to receive the next burst of neurotransmitters.
The neurotransmitters are then repackaged and reused the next time a message needs to be sent across the synapse. Even though this seems like a complicated set of steps, this entire information transmission cycle occurs in the brain within in a matter of seconds.
Any problem that interrupts the smooth functioning of this chain of chemical events can negatively impact both the brain and nervous system. Depression has been linked to problems or imbalances in the brain with regard to the neurotransmitters serotonin, norepinephrine, and dopamine.
What we do know is that antidepressant medications used to treat the symptoms of depression are known to act upon these particular neurotransmitters and their receptors. The neurotransmitter serotonin is involved in regulating many important physiological body-oriented functions, including sleep, aggression, eating, sexual behavior, and mood.
Serotonin is produced by serotonergic neurons. Current research suggests that a decrease in the production of serotonin by these neurons can cause depression in some people, and more specifically, a mood state that can cause some people to feel suicidal.
In the s, the "catecholamine hypothesis" was a popular explanation for why people developed depression.
This hypothesis suggested that a deficiency of the neurotransmitter norepinephrine also known as noradrenaline in certain areas of the brain was responsible for creating depressed mood.
More recent research suggests that there is indeed a subset of depressed people who have low levels of norepinephrine.
For example, autopsy studies show that people who have experienced multiple depressive episodes have fewer norepinephrinergic neurons than people who have no depressive history.
However, research results also tell us that not all people experience mood changes in response to decreased norepinephrine levels.
Some people who are depressed actually show hyperactivity within the neurons that produce norepinephrine. More current studies suggest that in some people, low levels of serotonin trigger a drop in norepinephrine levels, which then leads to depression.
Another line of research has investigated linkages between stress, depression, and norepinephrine. Norepinephrine helps our bodies to recognize and respond to stressful situations. The neurotransmitter dopamine is also linked to depression.
Dopamine plays an important role in regulating our drive to seek out rewards, as well as our ability to obtain a sense of pleasure.Clinical depression defines the state in which the depression symptoms must be treated by a doctor.
The causes of clinical depression are not specifically defined. However, as with the causes of depression in general, the causes of clinical depression are thought to be a combination of genetic, biological and environmental factors.
Clinical depression, also known as major depressive disorder, is the most common form of depression.
The Stanford School of Medicine estimates that 10 percent of Americans will experience this type of depression at some point in their lives. This type is also more likely to be shared by siblings and children. Depression is an extremely complex disease.
No one knows exactly what causes it, but it can occur for a variety of reasons. Some people experience depression during a serious medical illness. The causes of clinical depression include genetic/biological factors, psychological issues, environmental triggers, medical conditions, and some medications.
In most cases, no single cause is sufficient for depression to occur; rather a combination of factors make it more likely that a person will develop depression. General treatment information and guidelines to consider when seeking treatment for clinical depression, from self-help to psychotherapy to ECT.
of factors — personal, genetic, biological. Research suggests that depression doesn't spring from simply having too much or too little of certain brain chemicals. Rather, there are many possible causes of depression, including faulty mood regulation by the brain, genetic vulnerability, stressful life events, medications, and medical problems.