Well, it looks like at least one state is taking the United States Supreme Court's 2002 ruling in Atkins v. Virginia seriously. The Court ruled in Atkins that it was unconstitutional to execute the mentally retarded. However, the Court issued no standard for determining the parameters of mental retardation. The ruling has also caused some discussion over whether it applies to mental illness as well as mental retardation. Some states have seemed to just ignore the Atkins ruling altogether. For example, as you may recall, Texas recently executed Kelsey Patterson who was clearly seriously mentally ill. In contrast, according to this article, the State of Mississippi has increased the number of mental exams being done in capital cases. This is apparently happening to assure its cases fall in line with the Court's rulings. In fact, two death row inmates in Mississippi have had their sentences commuted to life due to the results of their post-Atkins mental examinations.

Mental exams in death penalty cases are more common