Biological Explanations of Depression

There are several biological explanations of depression but today we will discuss 3 in particular. But before we dive into the 3 explanations, what exactly is meant by biological explanation of depression?

Sometimes people say they think they were born with depression or have always felt sad since they were young.

These explanations may offer an answer to that statement in that depression may be explained by:

Evolution – depression may have offered an evolutionary advantage.
Genetics – depression may be passed on to children through genes.
Biochemical – chemical and substances are imbalanced that may contribute to depression.

Biological explanations of depression

Evolutionary Explanations of Depression

According to one theory known as the social competition hypothesis, depression throughout evolution has been a adaptive strategy to end prolonged conflict.

The hypothesis first proposed in 1994 suggests that depression may arise after a conflict (often physical) has been lost, the losing individual rather than continuing to fight on would retreat and therefore be protected from further conflict and danger.

This strategy would likely cause short term suffering in the form of depression but would ensure ongoing survival, however this theory does not account for prolonged depression lasting years that would likely inhibit survival.

An alternative view is offered by the social navigation theory, this theory suggest that depression offers a prolonged period of time for individuals (or groups) to think about their problems and come up with better solutions than they might previously have. Secondly the depressive state may signal help from others.

Genetic Explanations of Depression

Evidence suggesting genetics as an explanation of depression has been mixed, although we do know that from studying families, twins and adopted siblings that some evidence does exist.

For example one study looking at identical twins found they were more than twice as likely to both suffer from depression when compared with non-identical twins. 

Another study examining depression in families found that depression did run in families and that rate of depression was two to three times higher for children of parents who had suffered from depression in their life. 

One of the major difficulties in examining genetic factors for depression is due to the role of nature vs nurture.

For example – if we say that members of a certain family are likely to have an increased chance of suffering from depression then while that could be due to genetic factors, as they are likely to have grown up and been subjected to the same environmental factors its difficult to rule out nurture as the cause of the depression.

Biochemical Explanations of Depression

Biochemicals relate to the chemicals and substances within our bodies, we have a lot of different organs and processes producing these chemicals and substances in our bodies, we know that these substances effect both our mind as well as our physical bodies.

More specifically the neurotransmitters serotonin, dopamine, and noradrenaline play a key role in arousal and mood – if those change or do not perform as they should its like to impact our mood and over a period of time may be contribute to depression.

It has been demonstrated that by-products involved in the process of noradrenaline and serotonin neurotransmitters are lower in individuals with depression. 

So how do these Biological Explanations of Depression effect us?

While establishing a direct cause and effect for any of these explanations is difficult, we can say with some confidence that the three explanations are likely to be inextricably linked and that the sum of the explanations is significant to the causes of depression in people suffering from depression.