Daniel Carlat in his blog post of August 15 mentions, and critiques, a so-called blood test for depression marketed (for $745) by Ridge Diagnostics.
The essence of Dr. Carlat’s criticism is that the test is not predictive of depression, but merely enables one to tell (with some degree of accuracy) whether or not a person is depressed. Dr. Carlat makes the point that you can tell this with more or less total accuracy simply by asking the person if he is depressed or by observing him for a few minutes of conversation.
Dr. Carlat’s points are – as always – succinct and thoughtful, and his critique of Ridge’s expensive test is accurate and compelling. However, he is missing the point. The purpose in developing a test of this nature is not to predict or identify depression in individuals, but rather to promote the spurious notion that depression is a brain illness. One of the most telling criticisms consistently leveled against the psychiatric sand-castle is that there are no objective tests for these so-called illnesses. So along comes Ridge Diagnostics with a test which gets written up in the Psychiatric Times. Now it doesn’t matter that the test has no predictive value, has doubtful descriptive value, and is backed by little or no peer-reviewed research. What matters is that the notion has been pushed out there into the “idea-sphere” and will, if repeated often enough, enter public consciousness as a “reality.” And this “reality” serves to justify the psychiatrists’ wholesale drug-pushing.
But . . . having said all that, I am pleased to tell you that there is a blood test which predicts depression with 100% accuracy. It is simple, can be done at home, and costs nothing.
Here’s how it works. Prick your finger (sterile technique, of course). If you see blood, it is 100% guaranteed that at some time in the next five years you will experience a bout of depression.
The point being, as I have repeatedly stated, depression is a normal part of the human condition. The critical issue is what we do about an episode of depression. Do we wallow in it, or do we get up and get going? The answer to that question depends on the stimulus properties of the situation and on the individual’s reinforcement history.
And there is no blood test that will reliably discriminate the wallowers from the get up and goers.
I suppose if a person wallowed in depression for years and years it is conceivable that some physiological/anatomical alterations might occur, and these might be detectable in blood (or other tests). But, as I’ve said before, this is like visiting a tornado site and concluding that the high winds were caused by the wrecked houses.