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I am an Assistant Professor of Evolutionary Psychology, but I have a checkered educational past. My bachelor's degree is in Aerospace Engineering at the University of Arizona, and I received my law degree from the University of Illinois at Urbana-Champaign. I then pursued a PhD in Biology at the University of New Mexico, after which I did postdoctoral work in evolutionary psychology (University of New Mexico) and in psychiatric and behavioural genetics (Virginia Commonwealth University).

Paul AndrewsPaul Andrews, PhD, JD

Depression as an Adaptation for Analyzing Complex Problems

My primary research interest is understanding the evolution of depression. In 2009, I published a paper with Andy Thomson in Psychological Review that argues depression may be an evolved emotional response to complex problems, and its function is to promote changes in body systems that promote analysis of those problems. (You can download a manuscript version of the paper below.)

Media and popular coverage

Evolutionary analysis of the effects of antidepressant medications

Nearly all commonly prescribed antidepressant medications perturb serotonin—an ancient chemical that is found in plants, fungi, and animals. In recent work published in Frontiers in Psychology (you can download for free here), we have found that antidepressant medications have adverse health effects on every major process in the body regulated by serotonin including mood, attention, neuronal growth and death, reproductive functioning, electrolyte balance, digestive functioning, platelet activation and the clotting process. By interfering with numerous adaptive processes, antidepressants appear to degrade the overall functioning of the body. In the elderly, antidepressant use is associated with an increased risk of death, the magnitude of which is arguably greater than the risk of cardiac events caused by the painkiller Vioxx. Such evidence suggests that antidepressants do more harm than good.

Media and popular coverage

Relapse after Discontinuing Antidepressant Medication

We have also examined the risk of relapse after discontinuing antidepressant medication. (You can download the article we published in Frontiers in Psychology for free here.) The monoamines--serotonin, norepinephrine, and dopamine--are important neurotransmitters in the brain that have broad effects on how we think, feel, and behave, and they are thought to be involved in depression. Antidepressant medications attempt to reduce depressive symptoms by altering the levels of these neurotransmitters in the brain. My colleagues and I found evidence that the brain pushes back against antidepressant drugs in an attempt to keep monoamines at their pre-medication levels. When one stops taking antidepressant medications, the pressure causes an overshoot of symptoms, which corresponds to an increased risk of relapse--greater than the risk if one had not taken antidepressant medications in the first place. This work suggests that antidepressants can leave people stuck in a cycle where they have to continue taking the drugs to prevent this surge of symptoms.

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Sexual Infidelity, Suicidal Behavior

I also work on sexual infidelity, suicidal behavior, and other mental health traits from an evolutionary perspective.

Media and popular coverage

Adaptationism as a Strategy for Testing Adaptationist and Non-Adaptationist Hypotheses

A strong interest in evolutionary metatheory (e.g., how to test and choose between adaptationist and non-adaptationist hypotheses for traits) lies at the foundation of all my work. In 2002 I published a Behavioral and Brain Sciences paper (you can download it below) with Steve Gangestad and Dan Matthews that argues that adaptationism is not a commitment to the idea that a trait is an adaptation. Rather, it is a research strategy for testing whether or not a trait is an adaptation.

Selected Publications:

Andrews, P. W., Thomson, Jr., J. A., Amstadter, A., & Neale, M. C. (2012) Primum non nocere: an evolutionary analysis of whether antidepressants do more harm than good. Frontiers in Psychology 3, 117. doi: 10.3389/fpsyg.2012.00117 . Andrews_FP_2012

Andrews, P. W., Kornstein, S. G., Halberstadt, L. J., Gardner, C. O. & Neale, M. C. (2011). Blue again: Perturbational effects of antidepressants suggest monoaminergic homeostasis. Frontiers in Psychology, 2, 159. doi: 10.3389/fpsyg.2011.00159 . Andrews_FP_2011

Andrews, P. W., & Thomson, Jr., J. A. (2009). The bright side of being blue: Depression as an adaptation for analyzing complex problems. Psychological Review, 116(3), 620-654. Andrews_PR_2009

Andrews, P. W., Gangestad, S. W., Miller, G. F., Haselton, M. G., Thornhill, R., & Neale, M. C. (2008). Sex differences in detecting sexual infidelity: Results of a maximum likelihood method for analyzing the sensitivity of sex differences to underreporting. Human Nature, 19(4), 347-373. Andrews_HN_2008

Andrews, P. W. (2006). Parent-offspring conflict and cost-benefit analysis in adolescent suicidal behavior: Effects of birth order and dissatisfaction with mother on attempt incidence and severity. Human Nature, 17(2), 190-211. Andrews_HN_2006

Andrews, P. W., Gangestad, S. W., & Matthews, D. (2002). Adaptationism - How to carry out an exaptationist program. Behavioral and Brain Sciences, 25(4), 489-504. Target article. Andrews_BBS_2002

Recommended Websites:

Paul Andrews

Contact Information


905-525-9140, ext. 20820

Paul W. Andrews, PhD
Department of Psychology, Neuroscience & Behaviour
McMaster University
1280 Main Street W
Hamilton, Ontario L8S 4K1

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