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What Can Science Tell Us About Competency to Stand Trial?

Competency to Stand Trial

Competency to stand trial is a core issue which is prevalent in the areas of forensic psychology and mental health law (Cruise & Rogers, 1999). Determination of competency to stand trial is the most common inquiry associated with mental health in the criminal justice system (Chien et al., 2016). Competency to stand trial encompasses multiple factors that are explained in Psychological Evaluation for the Courts: A Handbook for Mental Health Professionals and Lawyers (Melton, Petrila, Poythress, & Slobogin, 2007). These factors include: understanding the current legal situation and charges; understanding the roles of defense counsel, the prosecuting attorney, the judge, the jury, the witnesses, and the defendant; understanding legal procedures and options available; the ability to bear stress and refrain from irrational behavior during trial; the capacity to utilize legal safeguards for self-protection; and the ability to make decisions based on advice and available information.

It is an established law in most of the countries across the world that criminal proceedings cannot be continued against an individual who is considered to be incompetent to stand trial. Through proper psychological interventions such individuals can regain the competence to stand trial. However, in some cases defendants remain incompetent to stand trial throughout their life (Heilbrun et al., 2021). The most common psychopathologies associated with incompetence to stand trial are intellectual disability and psychosis. However, not all the clients with these disorders are found to be incompetent to stand trial (Wall & Lee, 2020).

Importance of Competency to Stand Trial

The competency to stand trial primarily serves three purposes (Bonnie, 1992):

  1. Preservation of dignity of the criminal process - In the case of incompetence, the defendant cannot be held accountable. If proceedings are carried out in such a case, it is a mere act by the prosecution to give punishment and makes the judicial process questionable.

  2. Reducing the risk of false convictions - Competence ensures that outcomes of the judicial process are reliable.

  3. Protecting the decision-making autonomy of the defendant - Competence ensures that the defendant is aware of all the options available to him/her during the judicial proceedings. It ensures that the defendant makes independent decisions related to their plea, testimony, strategy, and so forth.

Role of a Forensic Psychologist

A psychologist that specializes in dealing with the criminal justice system and mental health law is known as a forensic psychologist. They have many duties which include mental disorder diagnosis, determining the severity and describing the nature of a mental disease/defect/disability, developing and articulating opinions regarding interference of the defendant’s mental condition with their ability to proceed in the criminal justice system, evaluating for malingering, and assessing the defendant’s potential for restoration of competency.

Assessment of Competency to Stand Trial

Assessment of a defendant requires many considerations, approaches, and sources of information. Often, formal checklists, standardized assessment tools (which frequently include forensic assessment instruments [FAIs]), clinical evaluation, and structured interviews are used for the assessment of competency to stand trial. The Evaluation of Competency to Stand Trial – Revised (ECST-R) and the MacArthur Competence Assessment Tool-Criminal Adjudication (Mac-CAT-CA) are examples of such FAIs. Other commonly used tools for assessment of competency to stand trial include the Competency Assessment Instrument (CAI), the Georgia Court Competence Test (GCCT), and the Competence Assessment for Standing Trial for Defendants with Mental Retardation or CAST*MR (Wall & Lee, 2020).

The core focus of these assessments is to understand the potential or capacity of the defendant, not merely the defendant’s current level of knowledge as it differs depending upon prior experience or exposure to the criminal justice system. The defendant’s cognitive abilities are also tested to make certain that they can make well informed and rational decisions. The assessment can sometimes be straightforward and other times be complex depending upon the nature of the problem (Hoge, 2016). In either case, inter-rater reliability of estimating competence of defendants is high among different psychologists (Rosenfeld & Wall, 1998). This implies that the decision given by a forensic psychologist regarding the competence to stand trial is generally accurate, unbiased, and depends on the functional ability of the defendant (Cooper & Zapf, 2003).

Factors Influencing Competency to Stand Trial

Cognitive factors associated with competence include memory, social judgement, and psychiatric symptoms. Individuals who are declared to be incompetent to stand trial have lower auditory memory. They also have higher levels of confusion, thought blocking, decreased sleep, heightened motor activity, concentration issues, and difficulty with sleep (Klein, Nestor, Lisak, & Holtzen, 2010). Additionally, verbal memory, abstract thinking, social knowledge, visuoperceptual skills, and cognitive processing speed predicted competence to stand trial (White, Meares, & Batchelor, 2013).

Demographic factors have a role to play in competence to stand trial. Research has shown that non-white defendants were 1.5 times more likely to be incompetent as compared to their white counterparts. Gender did not play any major role as men were as likely as women to be declared incompetent. Unemployed and unmarried defendants were found to be 2 times and 1.5 times, respectively, more likely to be incompetent as compared to employed and married defendants. Defendants having psychotic disorders were eight times more likely to be incompetent as compared to mentally healthy defendants (Pirelli, Gottdiener, & Zapf, 2011). Lower IQ levels and individuals who killed a relative or prison inmate were more likely to be declared incompetent to stand trial (Tartaro, Duntley, Medvetz, & Hafner, 2018).

In cases of juvenile offenders, younger age, diagnosis of psychosis, special education placement, and intellectual impairments were found to be determining factors for incompetence (Kruh, Sullivan, Ellis, Lexcen, & McClellan, 2012).

Factors Influencing Restoration of Competency to Stand Trial

Defendants who are declared as incompetent to stand trial are sent to state institutions for restoration of competence. Longer durations of hospitalization bring with it concerns related to financial cost and civil rights. As a result, it is important to find determinants that influence restoration of competency to stand trial. Studies have shown that successful restoration is associated with substance abuse and personality disorders. On the other hand, unsuccessful restoration is associated with prior state hospitalization, psychotic disorder, and intellectual disability (Morris & DeYoung, 2012). Criminal history and present violent charges are also factors which influence restoration of competency (Hubbard & Zapf, 2012).

In juvenile cases, IQ was found to be the best predictor of successful competency restoration. This implies that defendants with a high IQ score are likely to have higher chances of successful restoration as compared to those with lower IQ scores (Chien et al., 2016). The duration of restoration varies depending on different factors. Defendants with higher rates of juvenile conduct problems were likely to be restored within 90 days while higher rates of antisocial behavior predicted restoration at 90 days (Grossi, Green, Schneider, Belfi, & Segal, 2018).

Defendants having neurocognitive impairment at a mild to moderate level for orientation, memory, cognitive flexibility, attention, and processing speed were likely to have successful restoration. Severe impairment in these areas along with lower scores on visuospatial/constructional abilities led to unsuccessful restoration (Gilmore-Thomas, 2017). Another study using the Mini Mental State Examination to measure cognitive functioning reiterated that 90% of defendants with no to moderate cognitive impairment and 68% of defendants with severe cognitive impairment had successful restoration (Staats, Kivisto, & Connell, 2021).

For more information on the assessment of competency to stand trial and restoration, please do not hesitate to contact us at


Bonnie, R. J. (1992). The competence of criminal defendants: A theoretical reformulation. Behavioral Sciences & the Law, 10(3), 291–316.

Chien, J., Coker, K. L., Parke, S., Tejani, N., Sirken, R. A., Sanchez-Jaquez, C., Rausch, F., & Azeem, M. W. (2016). Predictors of Competency to Stand Trial in Connecticut’s Inpatient Juvenile Competency Restoration Program. Journal of the American Academy of Psychiatry and the Law, 44, 451–456.

Cooper, V. G., & Zapf, P. A. (2003). Predictor Variables in Competency to Stand Trial Decisions. Law and Human Behavior 2003 27:4, 27(4), 423–436.

Cruise, K., & Rogers, R. (1999). An analysis of competency to stand trial: an integration of case law and clinical knowledge - Cruise - 1998 - Behavioral Sciences & the Law - Wiley Online Library. Behavioral Sciences & the Law.;2-4

Gilmore-Thomas, A. (2017). Predictive Models Of Competence Restoration Using Neurocognition as a Mediator for Individuals Found Incompetent to Stand Trial in a Dissertation [A&M University].

Grossi, L. M., Green, D., Schneider, M., Belfi, B., & Segal, S. (2018). Personality, Psychiatric, and Cognitive Predictors of Length of Time for Competency to Stand Trial Restoration. Https://Doi.Org/10.1080/14999013.2018.1459964, 17(2), 167–180.

Hoge, S. (2016). Competence to stand trial: An overview. Indian Journal of Psychiatry, 58(Suppl 2), S187.

Hubbard, K. L., & Zapf, P. A. (2012). The Role of Demographic, Criminal, and Psychiatric Variables in Examiners’ Predictions of Restorability to Competency to Stand Trial. Http://Dx.Doi.Org/10.1080/14999013.2003.10471186, 2(2), 145–155.

Klein, K. L., Nestor, P., Lisak, D., & Holtzen, D. (2010). “Neuropsychological and Personality Predictors of Competence to Stand T” by Kristy L. Klein [University of Massachusetts Boston].

Kruh, I. P., Sullivan, L., Ellis, M., Lexcen, F., & McClellan, J. (2012). Juvenile Competence to Stand Trial: A Historical and Empirical Analysis of a Juvenile Forensic Evaluation Service. Http://Dx.Doi.Org/10.1080/14999013.2006.10471236, 5(2), 109–123.

Melton, G., Petrila, J., Poythress, N., & Slobogin, C. (2007). Psychological Evaluations for the Courts, Third Edition: A Handbook for ... - Gary B. Melton, John Petrila, Norman G. Poythress, Christopher Slobogin - Google Books (3rd ed.). Guilford Publications.

Morris, D. R., & Deyoung, N. J. (2012). Psycholegal Abilities and Restoration of Competence to Stand Trial. Behavioral Sciences & the Law, 30(6), 710–728.

Pirelli, G., Gottdiener, W. H., & Zapf, P. A. (2011). A Meta-Analytic review of competency to stand trial research. Psychology, Public Policy, and Law, 17(1), 1–53.

Porter Staats, M. L., Kivisto, A. J., & Connell, R. E. (2021). The role of cognitive functioning in predicting restoration among criminal defendants committed for inpatient restoration of competence to stand trial. International Journal of Law and Psychiatry, 74, 101654.

Rosenfeld, B., & Wall, A. (2016). Psychopathology and Competence to Stand Trial: Http://Dx.Doi.Org/10.1177/0093854898025004003, 25(4), 443–462.

Tartaro, C., Duntley, J., Medvetz, S., & Hafner, N. (2018). Factors that predict murder defendants’ competence to stand trial. International Journal of Law and Psychiatry, 59, 31–37.

Wall, B., & Lee, R. (2020). Assessing Competency To Stand Trial. Psychiatric Times, 37(10).

White, A. J., Meares, S., & Batchelor, J. (2014). The role of cognition in fitness to stand trial: a systematic review. Http://Dx.Doi.Org/10.1080/14789949.2013.868916, 25(1), 77–99.

Authored by

Marva Sohail Benjamin Silber

1 Comment

Eve Fritz
Eve Fritz
Mar 14, 2022

Ben, thank you for this new article. I appreciate the goals of competency assessments to protect autonomy and for a fair and just trial. So, would you say 90 days Is an average amount of time for an individual to be restored in most cases? Also, in regards to addicts, it comes to mind the term “90 and 90“ for alcoholics/ addicts to attend meetings is what is often suggested and I was curious if this type of rehab and meeting requirement is ever court ordered. Thank you!

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