Analysis shows which people most likely found incompetent to stand trial

"Competency to stand trial evaluations have been regarded as the most significant mental health inquiry pursued in the system of criminal law," said the paper's lead author, Gianni Pirelli, PhD, who conducted the research at John Jay College of Criminal Justice, City University of New York and is presently on staff at Greystone Park Psychiatric Hospital in New Jersey.

The paper, published in the APA journal Psychology, Public Policy and Law, examined results of 68 studies from 1967 to 2008 to help determine which variables are most closely related to findings of incompetency, as well as which measures are best to use in competency evaluations. Combined, the studies' participants totaled 26,139 individuals, with 6,428 found incompetent and 19,711 found competent. Only approximately half of the studies included female participants.

The current legal standard for competency to stand trial is based on a 1960 Supreme Court ruling in Dusky v. United States that determined a defendant is competent if "he has sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding -- and whether he has a rational as well as factual understanding of the proceedings against him," the article states.

The paper analyzed comparisons among demographic, psychiatric and criminal variables for competent and incompetent defendants. It found that defendants diagnosed with a psychotic disorder were approximately eight times more likely to be found incompetent, and unemployed defendants were twice as likely to be found incompetent. The likelihood of being found incompetent was also double for defendants with a previous psychiatric hospitalization.

Additionally, in contrast to a competent defendant, those found to be incompetent were slightly older, predominantly non-white and unmarried, the research showed. Regarding similarities between competent and incompetent defendants, the study found the majority were male, had a prior arrest history, a current violent criminal charge and an average of about 10 years of education.

Competency test data "must be integrated with information obtained from clinical interviews, other relevant test data and observation/reports from collateral sources," the authors wrote. They emphasized the importance of competency evaluations and the risks if these evaluations are conducted poorly, including allowing an incompetent defendant to stand trial or violating a defendant's civil rights by temporarily committing him or her to a psychiatric facility.