Wednesday, September 18, 2013

Navy Yard Shooter: Do Prescription Drugs Cause Violence?

Here's an article that looks at the rate of reports of violence associated with prescription drugs. The methodology is really iffy, and several authors are paid consultants for litigation. Bias from financial conflicts of interest is highly probable, especially given their unusual methodology for the determination of an association. Furthermore, the authors seem to intentionally blur the line between association and causation in their discussion and conclusions. Still, it is an interesting hypothesis (unproven by their research) that is worthy of further investigation.

The major flaw in this study is that we don't know whether or not a person with severe psychiatric problems is more, or less likely to commit violence when on or off the medication. It's possible that these are the medications prescribed to people with such tendencies, and that the overall effect of the medications is positive (i.e. reduces violence).

Let's look at this another way by hypothesizing that diabetic medications cause high blood sugar. We look at people on the diabetic medications, and compare them to people on blood pressure medications, and subsequently find that people on diabetic medications have higher blood sugar levels than people on blood pressure medications. In this situation, it is clearly wrong to conclude that the diabetic medications actually cause high blood sugar levels. However, there is an association because diabetic medications are only prescribed to diabetics, who because of their disease have high blood sugars. The medications may reduce blood sugar levels, but not down to the level of non-diabetics.

Just like it is really absurd to state that diabetic medications *cause* high blood sugar levels, it is wrong to conclude that psychiatric medications *cause* violence. Yes, there is an association, but perhaps the problem is that not enough diabetics are not on diabetic medications, and perhaps not enough people with psychiatric problems are on psychiatric medications.

Association does not equal causation, it's as simple as that.

PLOS ONE: Prescription Drugs Associated with Reports of Violence Towards Others

Tuesday, September 3, 2013

What's wrong with this?

I just read this online...

"Dysuria, or painful urination, is usually the chief complaint in men with urethritis, and is reported in the majority of men with gonorrhea and over half of patients with nongonococcal urethritis."


The majority of men with gonorrhea have dysuria.


Over half of patients with nongonococcal urethritis have dysuria.