College 4: why do humans get depressed?

Question 1

Evolution and depression

Answer 1

Depression is common (18%), heritability (37%), which is why you would think that it is functional. But people with depression get less children –> lower change of procreation.

Question 2

The function of depression

Answer 2

• Cry for help
• Reaction to losses
• Seasonal > no activity in the winter
• Energy conservation
• Rumination > solving problems
• Association with inflammations/infections
• Mismacht

Question 3

Inflammation and depression

Answer 3

People in modern society don’t die from infections anymore, but we can still experience inflammatory responses. We still get wounds / infection from stressful situations, which causes an overactive immune system. This is also present in people with depression.

Question 4

Unified model of depression (Beck)

Answer 4

In depression there is always a stressor involved. This stressor leads to negative cognitive appraisals. This can cause negative automatic thoughts in people who are vulnerable for depression. Your immune system starts to response at the same time, which causes sickness behaviour. The main function of depression therefor is energy conversation.

Question 5

Mismatch hypothesis

Answer 5

We are not adapted to modern environments, but to ancestral environments. This results in a mismatch.

Question 6

Environment of evolutionary adaptedness (EEA)

Answer 6

In history, these were the normal environmental circumstances:

• Savannah-like environment
• Hunter-gatherer society
• Nomadic lifestyle
• Physical dangers
• High infant mortality
• Food scarcity

Question 7

Mismatch 1: chimpanzees in the wild vs. chimpanzees in captivity.

Answer 7

Chimpanzees in the wild were less depressed, because there is less mismatch between their environment.

Question 8

Mismatch 2: developing countries vs. developed countries.

Answer 8

In developing countries people still live more in line with how our ancestors lived. This is why there are higher rates of depression among people who make more money.

Question 9

Mismatch 3: rural area’s vs. urban area’s

Answer 9

There is a higher rate of depression in urban area’s, because there is more mismatch between those area’s and the area’s in which our ancestors lived. This also depends on:
- Poverty
- Immigration
- Green space availability

Question 10

Mismatch 4: hunter-gatherer societies vs. modern societies

Answer 10

Hunter gatherer-societies in remote places have almost no occurrence of depression. There was more depression in after modernisation.

Question 11

Mismatch 5: co-sleeping babies vs. babies sleeping alone

Answer 11

Co-sleeping causes more secure attachment to the caregivers, less stress, lowers cortisol levels and are more in natural synchrony with their child –> les mismatch.
But:
- The child could develop separation anxiety.
- Privacy problems.

Question 12

Mismatch 6: no physical activity vs. physical activity

Answer 12

If the physical activity is congruent with the activity of the hunter-gatherers, there should be less mismatch. The risk of getting certain diseases is indeed lower when you get enough physical exercise. Depressive symptoms also decrease with more physical activity: moderate exercise and high intensity both work.

Question 13

Mismatches that increase the change of depression

Answer 13

• Lack of time
• Worrying
• Lack of freedom
• Lack of joy
• Social media addiction
• Deviant youth
• Unhealthy habits

Question 14

Best predictors of depression

Answer 14

1. Lack of freedom
2. Lack of time
3. Worrying
4. Processed food
5. Sleep rhythm
6. Perfectionising

–> High sensitivity is a moderator.

Question 15

University students and mismatches

Answer 15

Prevalence of depression in students = 30%

Students have quite a lot of mismatches in their life and therefore a higher change of depression.

Question 16

Mildfullness

Answer 16

Improves symptoms of all kinds of disorders and prevents depressive relapse.