There is evidence that people who have firearms in their homes are more likely to kill themselves than people who don't. But correlation is not causation.

If people who have library cards read more books than people who don't, that doesn't mean getting a card causes people to read. People who read a lot, after all, tend to have library cards. It may be that people who are prone to suicide are more inclined to buy guns -- not that people who buy guns are more prone to suicide.

A recent report by the Rand Corp., a California-based think tank, said, "Available empirical research does not provide strong causal evidence for the effects of gun prevalence on suicide risk."

Here's another factor, noted by scholars in the Journal of Epidemiology and Community Health: "Suicidal individuals vary in the strength of their intention to die, which can influence their choice of a suicide method." Firearms tend to be preferred by those most determined to die. Depriving these unfortunates of guns would not make them want to live.

In any case, the sort of gun control measures that are politically conceivable in the United States would be irrelevant. We could ban semi-automatic "assault weapons" or 15-round magazines, but neither is needed by those who want to shoot themselves.

There are many ways to combat the scourge of suicide: facilitating mental health care, substance abuse treatment, employment and social support. Focusing on firearms is missing the point.