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Depression as an evolutionary strategy for defense against infection
Sherry Anders1, Midori Tanaka, Dennis K Kinney
1Clinical Psychologist in Independent Practice, Boxborough, MA, USA.
Brain, Behavior, and Immunity
|December 25, 2012
Summary
Depression may be common and heritable because it evolved as an adaptive defense against infections. This infection-defense hypothesis explains mood disorders and their links to immune function.
Area of Science:
- Evolutionary biology
- Neuroscience
- Immunology
Background:
- Depression is common and heritable, posing an evolutionary puzzle.
- Negative consequences of depression suggest a strong selective pressure against it.
- The infection-defense hypothesis offers a potential evolutionary explanation.
Purpose of the Study:
- To review the infection-defense hypothesis of depression.
- To explore the adaptive role of mood in fighting infections.
- To explain depression's links to immune function and other conditions.
Main Methods:
- Review of existing literature on depression, inflammation, and immune function.
- Analysis of evidence supporting the infection-defense hypothesis.
- Comparison with other evolutionary theories of depression.
Main Results:
- The infection-defense hypothesis provides a framework for understanding depression's evolutionary persistence.
- It explains the bidirectional communication between nervous and immune systems.
- It accounts for depression's associations with various illnesses and conditions.
Conclusions:
- Depression may have evolved as an adaptive mechanism for infection defense.
- Mood states orchestrate responses to combat and avoid infections.
- This hypothesis has implications for depression treatment and prevention.
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