Do Life Events "Cause" Depression?
A huge literature base on life events and depression shows that the vast majority of depressive episodes occur with a preceding life event that "causes" that depression. What are those life events? Trouble with a spouse, a boss, or a child; financial problems; medical illness. So those life events cause depression. And who doesn't have those life events? The question should not be why those life events cause depression, but why they don't cause depression in the 90% of the population that never experiences a severe clinical depressive episode.
Obviously, something else is at work. Contrary to all the hopes and wishes of psychologizers, there is such a thing as biology. The ultimate proofs of the psychological fallacy are the split-brain experiments.
In the 1970s and 1980s, some patients with severe epilepsy were treated with corpus callosotomy, so as to prevent spread of seizure activity from one hemisphere to the other and thereby prevent generalized convulsions. This surgery allowed some interesting neuropsychological research. By showing a picture, such as a woman talking on the telephone, to the left visual field of a right-handed split-brain patient, one could test how the patient would report that knowledge. The information could not be transmitted from the right cerebral hemisphere to the left, where the language areas mainly are in right-handed persons.
In such a test, the patient would say that she saw something different, such as a boy playing with a ball. But if asked to show what she saw, she would pick up a telephone with her left hand. She got the information, but she couldn't say it.
More important, instead of simply admitting that she couldn't say it, she made something up. The patient confabulated. That is what the human brain does. As Michael Gazzaniga, the main researcher on this topic said, the brain is a rationalizing machine. We come up with reasons for everything. Sometimes we're right, sometimes we're not, and we don't know which is which in any one case. The mere fact that we can come up with a coherent, logical, explanation for any experience means quite little; of course we can, we always can.
But sometimes common-sense explanations are false, especially when something else is at work -- for example, biology, or a disease of the body. Psychosocial life events can influence the timing of a depressive episode, but if someone has repeated depression, biology is the underlying cause of the predisposition to those episodes. That's why 10% have episodes with the same life event that doesn't cause episodes in 90%.
That's why we have to take disease concepts seriously in psychiatry, and we have to accept biology and not constantly write it off as reductionism. Psychological reductionism exists too, and we seem to biologically hard-wired for it.
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Cite this: Fallacies of Psychiatry - Medscape - Oct 04, 2013.