NADD Bulletin Volume III Number 1 Article 1

Complete listing

Barriers to Being, Becoming, and Remaining Competent to Stand Trial

Stu Smith, PhD

To determine whether a defendant can help develop an adequate enough defense to receive a fair trial, an evaluation of Competency to Stand Trial (CST) may be requested. This evaluation provides the court with an expert’s opinion about the extent of the defendant’s factual and rational knowledge of court proceedings, as well as his/her ability to consult with an attorney (Dusky v US., 1960). If the conclusion is not CST, an opinion is requested about the likelihood of becoming CST in the “foreseeable future” (Jackson v Indiana, 1972). Many states define this as about one year (Grisso, 1998). Criminal Responsibility is also often assessed, which refers to whether a mental defect impaired the defendant’s knowledge of right from wrong, at the time of the offense (American Bar Association, 1989).

Defendants with mental retardation experience many problems when facing the criminal justice system (Brown & Courtless, 1971; Conley, Luckasson, & Bouthilet, 1992; Denkowski & Denkowski, 1985; Ellis & Luckasson, 1985; Smith & Broughton, 1994). With respect to CST, Baroff and Freedman (1988), as well as Grisso (1997), doubt whether very many juveniles or adults with IQs below 70 and Mental Ages below 12 to 14 can really be CST, or can even adequately understand the Miranda warnings upon arrest. The scarcity of relevant research, most of which is fragmentary, unreplicated, and of limited generalizability, leaves this issue unresolved. A related additional problem is the lack of objective instruments with acceptable reliability and validity for determining CST in this population. Most have been developed for defendants without mental retardation, and thus present significant problems (Grisso, 1986). A promising exception is the CAST MR (Everington & Luckasson, 1992), but research on its usefulness is still limited.

Scientifically sound CST instruments might become critical if a strict enforcement of “get tough laws,” with mandatory sentences, waiver of violent juveniles to adult criminal court, and “three strikes and you’re out” provisions becomes popular, as has happened in California. Defense attorneys might more often request CST evaluations of defendants suspected of having cognitive impairments, in the hope of avoiding very harsh sentences. If the offense had been violent or sexual, prosecutors might begin to question CST evaluators more stringently, especially when their opinion is not CST and the defendant might return soon to the community. In such cases, the judge would value valid, objective data to support the final competency decision. Without these data, the judge faces two “worst scenarios”: (1) an erroneous decision of not CST might result in a dangerous person soon being free and (2) an erroneous decision of CST might result in an inadequate defense during a trial, and an innocent person might spend a long time in a harsh prison.

To gain a clearer, more objective understanding of what both CST and not CST defendants with mental retardation experience when facing a trial, the present study assessed their factual knowledge. Given the growth of “get tough laws” and the possibility that more defendants will face a judge who will want a more empirically based justification for an expert’s opinions, this information might be very helpful to developers of CST instruments. It might also benefit the attorney who wants to know what areas the CST client might need to strengthen, in order to improve court performance. Information from this study also might be helpful in determining whether the not CST client is likely to become competent with training in the foreseeable future. If deficits in factual knowledge are severe, the chance of achieving success in teaching the more complicated rational knowledge in the foreseeable future would likely be remote, at best.


Court-ordered CST evaluation protocols were retrieved from the files of 55 defendants with mental retardation who had been charged with felonies. Mean age was 27.4 yr. (n = 55, SD = 9.5), mean Wechsler Full Scale IQ 60.90 (n = 52, SD = 6.03), and mean Vineland Adaptive Behavior Scales Composite Age Equivalent 6.9 yr. (n = 35, SD = 2.1). All defendants had been evaluated by two psychologists jointly. Thirty were judged competent and 25 not competent to stand trial.

Knowledge of 18 important court-related terms and concepts was rated on a 0 to 4 scale by two psychologists independently. A rating of 0 or 1 was given for a complete or nearly complete lack of knowledge about the item, and 3 or 4 for a reasonable or very accurate definition. A 2 was given if an answer reflected some confusion but contained elements of the correct definition. For analyses, 0 and 1 ratings were combined, as were 3 and 4 ratings. This method separated those who clearly lacked knowledge from those who clearly had reasonable knowledge of an item. Interrater agreement was 91%.


As can be seen in the Table, not only were there significant t test differences between the CST and not CST on nearly all items, but the not CST persons had very inadequate knowledge on nearly half the items. A mean rating for this group of less than 1.5 was obtained on nine items, including the critical adversarial-related concepts trial, jury, and prosecutor. Even the crucial terms guilty and not guilty had a fairly low rating of 2.48 and 2.44. Only lawyer and proper courtroom behavior received a rating as high as 3. In contrast, a mean rating of 3 to 4 was achieved by the CST group on twelve items, and only two received a rating lower than 2. Important terms rated lower than a 3 (trial, jury, probation) were able to be understood well enough after explanation by the evaluators to warrant a final opinion of CST.


The Dusky standard for CST requires both adequate factual and rational court-related knowledge. Although the present data are concerned primarily with the former, the not CST had such severe deficits that it is unlikely that many would ever be able to gain both a factual and the more complex rational knowledge in a “foreseeable future.” This supports unpublished data from the Institute of Law, Psychiatry, and Public Policy (1989). They reported that only 16% of their 38 not CST defendants with moderate to mild mental retardation were likely to become CST. Success would certainly require some intensive and innovative training for defendants with mental retardation. There is no published listing of such sophisticated programs, and probably few are available. Most training programs appear to be within the mental health system, and do not focus on the special needs of defendants with mental retardation. If 30 to 35% of defendants with mental retardation are not CST (Petrella, 1992; Sauget, Wightman, & Everett, 1988; Smith & Broughton, 1994; Thompson & Boersma, 1988), the number of defendants would appear to far exceed the supply of such programs.

Important issues and research directions: In addition to a valid assessment of knowledge during the CST evaluation, other important court-related problems are in need of further exploration, especially with respect to the not CST Several follow:

Language deficits. Performance during a typical CST evaluation, or in a specialized training program that offers patience and learning at a pace the defendant can follow, might differ significantly from that in actual court. The defendant, who usually has a far less than average grasp of language, must be able to listen to and comprehend testimony and proceedings, in order to consult effectively with an attorney during a trial. Not being able to follow testimony carefully might result in erroneous testimony not being noticed or challenged. This can be a severe problem for the not CST, even if they have gained factual and rational knowledge in a training program. We recently analyzed Wechsler Full Scale IQs of 234 CST defendants and 102 not CST defendants and found a mean of 63.7 (SD = 6.9) for the former and 56.9 (SD = 6.9) for the latter. Verbal IQs were 65.5 (SD = 6.5) and 60.2 (SD = 6.8), respectively. The significantly lower scores of the not CST would likely predict serious problems in functioning effectively in a verbally charged court setting. An additional limitation in language skill was discovered when we rated the verbal fluency and clarity of 51 defendants from our sample on a 1 to 4 scale. While only 3 of the 30 CST defendants received a 2 or less, 10 of the 21 not CST received such scores.

In summary, the low ratings on the 18 court-related terms, the low Full Scale and Verbal IQs, and the poor expressive fluency suggest serious disadvantages in court. In a typical trial, with a normal pace of testimony, many of the formerly not CST defendants who might have gained sufficient factual and rational knowledge in a special CST training program would probably still not be able to defend themselves adequately. They might understand some words (if simple), but miss or misunderstand many others. They might understand some simple phrases and sentences, but miss or misunderstand many others. During our evaluations, communicating effectively with not CST defendants has typically required much simplification, repetition, and patience. At times, this has also been the case with CST defendants. In a sense, we have often acted as interpreters. In our experience, most courts are not willing to go to such lengths.

Length of time to trial. Another problem needing more investigation relates to the time between the offense and the actual trial. Smith and Broughton (1994) reported a 5 year mean of 113 days between the day of the offense and the court order for a CST evaluation. Another three months passed before the day in court. Over the next five years following our analysis, the mean time from the day of the offense and the court order for a CST evaluation of 313 defendants increased to 184 days. Defendants with cognitive deficits tend to have attention and memory problems, and not having a speedy trial can result in forgetting or confusing many details surrounding the alleged offense. If innocent, trying to answer accurately questions such as, “where were you, and what were you doing on that day and at that time?” might be nearly impossible, and might make a jury suspect lying and guilt. Even innocent people without cognitive deficits would probably have difficulty recalling this information, unless something unusual or dramatic had occurred. Such memory problems might be very severe for the not CST who, after going through a lengthy CST training program, would be asked to recall details about events that have become even more remote in time.

Preserving competency. Another barrier to competency might occur if the person remains in detention for a lengthy time. (Nearly all the defendants we have evaluated have been too poor to afford bond and have remained in detention until trial.) A good deal of erroneous information from peers about court and the criminal justice system might be heard and learned during this long period. We have occasionally found this to happen but do not know the actual prevalence. Whether CST or not, hearing erroneous information might well confuse a defendant and make it very difficult to consult with an attorney or perform effectively in court. If not CST, proactive interference from erroneous information might then cause even more problems in learning and retaining correct information while in a specialized CST training program. During a lengthy delay between graduation from the program and the day in court, preserving competency skills might become an important consideration, especially if the defendant must return to the detention center, and overhears conflicting and erroneous court-related information. If called to testify about the competency opinion, the evaluator might find it very useful to interview the defendant briefly beforehand, in order to determine whether competency has been lost.

Finally, the ability to attend and remain competent during a lengthy trial ,whether previously judged CST or not CST, needs to be studied. Complicated trials may last many hours or days, which can even tax the alertness and attention of jurors and attorneys. If unable to pay close attention during important testimony, the defendant would not be able to consult closely with the attorney, and an effective defense would be compromised.

Given the complexity of many trials and the many potential problems faced by CST, and especially by not CST defendants, perhaps the opinion that few defendants with IQs below 70 or Mental Ages below 12 to 14 really are Competent to Stand Trial is not a great exaggeration. If “get tough laws” do begin to have a significant impact on the fate of defendants with mental retardation, more research into this assertion will be particularly important. The development of more objective, reliable, valid competency instruments, as well as a clearer idea of which defendants are most likely to be incompetent and which are unlikely to profit from competency training should minimize the chances that a defendant who really is not CST (1) receives a harsh sentence because of an inability to understand court proceedings adequately and consult with an attorney effectively, or (2) spends unnecessarytime in detention while being trained to be competent with a program that is likely to fail.


American Bar Association. (1989) ABA criminal justice mental health standards. (2°d ed.) Washington, DC: Author.

Baroff, G., & Freedman, S. (1988, April) Mental retardation and Miranda. The Champion, pp. 6-9.

Brown, B. S., & Courtless, T. F. (1971) Mentally retarded offenders. Washington, DC: National Institute of Mental Health, Center for Studies of Crime and Delinquency.

Conley, R. W., Luckasson, R., & Bouthilet, G. N. (Eds.) (1992). The criminal justice system and mental retardation. Baltimore, MD: Brookes.

Denkowski, G. C., & Denkowski, K. M. (1985) The mentally retarded offender in the state prison system: identification, prevalence, adjustment, and rehabilitation. Criminal Justice and Behavior, 12, 53-70.

Dusky v. United States, 36 U.S. 402 (1960).

Ellis, J., & Luckasson, R. (1985) Mentally retarded criminal defendants. The George Washington Law Review, 53, 414-493.

Everington, C. T., & Luckasson, R. (1992) Competence Assessment for Standing Trial for Defendants with Mental Retardation (CAST-MR). Worthington, OH: International Diagnostic Systems.

Grisso, T. (1986) Evaluating competencies: forensic assessments and instruments. New York: Plenum.

Grisso, T. (1997) The competence of adolescents as trial defendants. Psychology, Public Policy, and Law, 3, 3-32.

Grisso, T. (1998) Forensic evaluation of juveniles. Sarasota, FL: Professional Resource Exchange, Inc.

Institute of Law, Psychiatry, & Public Policy (1989). Unpublished raw data. Charlottesville: University of Virginia.

Jackson v. Indiana, 406 U.S. 715 (1972).

Petrella, R.C. (1992) Defendants with mental retardation in the forensic services system. In R. W. Conley, R. Luckasson, & G. N. Bouthilet (Eds.), The criminal justice system and mental retardation. Baltimore, MD: Brookes.

Sauget, M. F., Wightman, L. H., & Everett, M. (1988) Comparison of competent and incompetent mentally retarded defendants. Unpublished manuscript, Center for Forensic Psychiatry, Ann Arbor, MI.

Smith, S. A., & Broughton, S. F. (1994) Competency to stand trial and criminal responsibility: An analysis in South Carolina. Mental Retardation, 32, 281-287.

Thompson, J. S., & Boersma, D. C. (1988). Competence to stand trial and the mentally retarded defendant: An empirical investigation. Unpublished manuscript, Center for Forensic Psychiatry, Ann Arbor, MI.

For more information contact:

Stu Smith, Ph.D.
Chief Psychologist, PeeDee Developmental Center
408 North Main Street
Darlington, SC 29532