Intellectual deficits and restoration to competency to stand trial: An examination of IQ cut off scores

Abstract

Intellectual functioning impacts defendants’ competence to stand trial, though research on this population remains limited. This study replicated and advanced prior work, focusing on defendants’ demographic, clinical, cognitive, and criminal justice variables and their association with length of hospitalization and restoration determinations. Participants were 74 male and female criminal defendants in a midwestern state who were adjudicated incompetent to stand trial, had a diagnosis related to intellectual deficits, and completed competency restoration. Most defendants (83.7%) were restored to competency. Demographic factors were unrelated to restoration outcomes; violence of alleged offense predicted shorter hospitalization. Receiver Operating Characteristic Curve analyses determined an IQ score cut-off of 63.5 for which participants were of greater likelihood to be determined restored, providing guidance on the likelihood of restoration for defendants with intellectual disability related diagnoses. Specifically, this score can be used with clinical data to inform competency determinations for defendants with cognitive deficits.

Keywords

competency restoration competency to stand trial intellectual deficits intellectual disability

Introduction

Competency to stand trial focuses on the defendant’s current mental state and functional ability to participate in legal proceedings. A defendant is most commonly defined as incompetent to stand trial if they do not have “sufficient present ability to consult with his lawyer with a reasonable degree of rational understanding” and “a rational as well as factual understanding of the proceedings against him,” but state statute sets specific requirements (Dusky v. United States, 1960, p. 362). When a defendant is determined to be incompetent to stand trial, they typically receive court-ordered treatment services aimed at restoring them to competence, such as psychotropic medication and legal education. A subpopulation of these individuals is unable to reach the threshold for competency and are ultimately not restorable.

The number of individuals who are both referred for competency to stand trial evaluations and found incompetent to stand trial is rapidly increasing and consequently burdening our legal and mental health systems (Callahan & Pinals, 2020; Melton et al., 2017; Pirelli & Zapf, 2020; Zapf et al., 2014). The past 15 to 20 years has produced a substantial increase in annual competency evaluations in the United States, with reports estimating 25,634 to 51,500 evaluations per year nationally (Fitch, 2014; Warren, Chauhan, Kois, Dibble, Knighton, 2013). Defendants hospitalized for a competency to stand trial evaluation lose significant civil liberties and face prolonged restoration processes, which infringe upon defendant’s due process rights such as the right to a speedy trial (Jackson v. Indiana, 1972). Furthermore, competency restoration, particularly inpatient services, incurs a high financial cost for taxpayers and state mental health systems. Thus, it is important to better understand and more effectively predict competency restoration outcomes to help inform mental health practitioners’ and courts’ decision-making during restoration (e.g., the length of hospitalization needed, on average, for defendants to be restored to competency). Better understanding of the factors and predictors associated with competency restoration, or failed restoration efforts, will improve both clinical and legal decision-making.

Competency restoration outcomes

Whereas literature about predictors for initial competency determinations is well-established, the literature about predictors of competency restoration outcomes is still emerging (Heilbrun et al., 2019; Pirelli & Zapf, 2020; Upton et al., 2020; Zapf & Roesch, 2011). Generally, the research has focused on differentiating defendants who are restorable from those who are not restorable. Notably, most research defines restorability as opined by evaluators rather than by legal determinations. Research examining the length of hospitalization for competency restoration is more limited but also important, particularly considering recent lawsuits regarding overcrowding and extreme wait times for restoration and the infringement on civil liberties (Center for Legal Advocacy DBA Disability Law Colorado v et al., 2019; Gowensmith, 2019; Trueblood v. State of Washington Department of Human and Social Services, 2015).

Psychotic disorders and symptomatology, chronic mental illness, dementia, and developmental disorders have been found to characterize defendants who are not restorable (Advokat et al., 2012; Anderson & Hewitt, 2002; Colwell & Gianesini, 2011; Gay et al., 2017; Morris & DeYoung, 2012; Morris & Parker, 2008; Ryba & Zapf, 2011; Warren et al., 2013). Defendants adjudicated not restorable also generally have a more extensive history of prior psychiatric hospitalizations (Colwell & Gianesini, 2011; Hubbard et al., 2003). Additionally, psychotic disorders are significantly related to increased length of hospitalization (Colwell & Gianesini, 2011; Nicholson & McNulty, 1992; Nicholson et al., 1994; Warren et al., 2006; Warren et al., 2013).

It has been found that demographic factors are not significant predictors of restorability or length of restoration (Advokat et al., 2012; Carbonell et al., 1992; Colwell & Gianesini, 2011; Warren et al., 2006); however, several studies found age, race/ethnicity, and gender to be associated with competency outcomes (Colwell & Gianesini, 2011; Morris & Parker, 2008; McCallum et al., 2015; Morris & Parker, 2009; Warren et al., 2006). Findings are also mixed in regard to criminal justice variables, with some studies finding nonsignificant relationships, some studies finding that a more extensive criminal history was related to determinations of restorability, and some studies finding that the severity of the index offense is a significant predictor of restoration outcomes (Advokat et al., 2012; Colwell & Gianesini, 2011; Hubbard et al., 2003; Warren et al., 2006).

Intellectual deficits and competency to stand trial

Intellectual deficits and Intellectual Disability Disorder (formerly Mental Retardation) have been consistently identified as relevant factors for competency to stand trial and restoration. For example, individuals with intellectual deficits may have difficulty comprehending and retaining relevant legal concepts and engaging in complex decision making in the legal system (Anderson & Hewitt, 2002; Cooper & Zapf, 2003; Everington et al., 2007; Fett, 2020; Heilbrun et al., 2019; Salekin et al., 2010; Upton et al., 2020). Defendants diagnosed with Intellectual Disability Disorder are less likely to be restored than their peers without an Intellectual Disability Disorder (e.g., Bonnie, 1992; Colwell & Gianesini, 2011; Mosotho et al., 2020; Mossman, 2007; Wolber, 2008). Defendants with more severe deficits, often measured by IQ or based on categorical severity signifiers in diagnoses, have been found more likely to be determined incompetent (Anderson & Hewitt, 2002; Colwell & Gianesini, 2011; Everington et al., 2007; Ho, 1996; Ho & Henderson, 1998; Mosotho et al., 2020; Porter Staats et al., 2021; Warren et al., 1997) — though some studies have found only a weak or nonsignificant relationship (Advokat et al., 2012; Grossi et al., 2018; Mehl, 1981; Nicholson & Kugler, 1991). Defendants with lower cognitive functioning, as measured by other cognitive assessments beyond IQ tests, are also less likely to be restored and are typically hospitalized longer for restoration services (Anderson & Hewitt, 2002; Colwell & Gianesini, 2011; Ho & Henderson, 1998; Porter Staats et al., 2021; Toofanian Ross et al., 2015).

Studies have investigated other variables and their relationships with outcomes for this subpopulation. For example, one study found that race/ethnicity is a significant predictor of competency restoration of defendants diagnosed with an Intellectual Disability Disorder (Anderson & Hewitt, 2002); whereas, another found no relationship between race/ethnicity and competency restoration outcomes (Ho, 1996). Anderson (1999) found that defendants diagnosed with an Intellectual Disability Disorder and an alleged offense involving a non-sexual contact crime against another person (e.g., assault) were more likely to be restored; whereas, defendants with an Intellectual Disability Disorder who were charged with a sex offense were less likely to be restored. Anderson (1999) also found that defendants with a comorbid Intellectual Disability Disorder and psychotic or alcohol use disorder were more likely to be restored than defendants without these co-occurring diagnoses, and defendants with Intellectual Disability Disorder with previous psychiatric hospitalizations were more likely to be restored than those with fewer or no prior psychiatric hospitalizations.

Current study

Research is needed to replicate prior findings and further elucidate how intellectual functioning and intellectual deficits relate to competency restoration outcomes and practitioners’ predictions of restorability. The purpose of this study is to (1) examine the association of competency restoration outcomes and length of hospitalization with demographic variables, criminal justice variables, clinical variables, and intellectual functioning for defendants who are incompetent to stand trial and have a diagnosis related to intellectual deficits and (2) explore what IQ score cut-off maximizes the sensitivity and specificity of correctly classifying individuals as restorable to competency to stand trial. Identifying this IQ score will aid clinicians in determining the point at which a defendant is less likely to be restored to competency.

Method

Participants

Archival data were used from 74 male and female criminal defendants with a diagnosis related to intellectual deficits who completed competency restoration services at a maximum-security state hospital in Missouri. Files were reviewed for individuals who were at the hospital from 2000 to 2014, which was determined based on document availability in hospital records systems. Competency restoration services at this hospital consisted of five psychoeducational competency restoration groups per week, weekly contact with a social worker for case management, and weekly consultation with a psychiatrist for medication assessment.

Inclusion criteria were that participants (1) were found incompetent to stand trial, (2) were committed for competency restoration, (3) completed competency restoration and were determined to be restored or permanently not restorable according to Missouri statute, which is when there is not a substantial probability that the defendant will be restored to competency within a reasonably foreseeable future (Missouri Revised, 2023), and (4) received a diagnosis related to intellectual deficits (e.g., Intellectual Disability, Borderline Intellectual Functioning) based on a prior standardized, individual intelligence test, such as a Wechsler Adult Intelligence Scale (Wechsler, 2008) with a documented full-scale IQ score. For determining inclusion criteria, diagnoses were based on the most current Diagnostic and Statistical Manual (DSM) criteria at the time of the report (i.e., DSM-IV-TR for reports contained in the file from 2000 to 2014; American Psychiatric Association, 2000). Documentation for defendants often had variations in diagnostic labels across multiple reports (e.g., a defendant was initially diagnosed with an “Intellectual Disability” that later changed to “borderline intellectual functioning” or vice versa). To understand and analyze a broader spectrum of intellectual functioning, all such participants were included in this sample, so long as they had a documented intellectual deficit in their facility record. Of note, impairment in adaptive functioning (life skills required to navigate through our environments) is required for a diagnosis of an Intellectual Disability, but many reports did not consistently reference a specific assessment of adaptive functioning (American Psychiatric Association, 2022). Because adaptive functioning information was largely unavailable in client files, the current study emphasized the cognitive component of intellectual deficits.

Participants ranged in age from 17 to 68, with a mean age of 30.68 (SD = 11.60). The majority of patients were male (n = 64, 86.4%) and White/Not Hispanic (n = 49, 66.2%) or Black (n = 22, 29.7%); two participants (2.7%) were White/Hispanic, and one was biracial (1.3%). Current charges were predominantly violent (n = 57, 77.0%) and nonsexual (n = 43, 58.1%) in nature. The majority of participants had a comorbid diagnosis in addition to their diagnosis pertaining to intellectual deficits (n = 56, 75.6%). Specifically, 15 participants were diagnosed with a substance related disorder (20.2%), 10 with Antisocial Personality Disorder (13.5%), 7 with another psychotic disorder (9.4%), 7 with a depressive disorder (9.4%), 4 with Schizophrenia (5.4%), 2 with Posttraumatic Stress Disorder (2.7%), and 1 with an anxiety disorder (1.3%). See Table 1 for additional information about the study’s sample demographics.

Table 1.

Study Sample Data.

Variable	n	%	M (SD)
Age (years)	74		30.68 (11.60)
Sex
Male	64	86.40
Female	10	13.60
Race
White/Non-Hispanic	49	66.20
Black	22	29.70
White/Hispanic	2	2.70
Biracial	1	1.30
Violent Crime*	57	77.00
Nonviolent Crime*	17	23.00
Sex Crime	31	41.90
Nonsex Crime	43	58.10
IQ Score	74		65.38 (6.90)
Comorbid Diagnosis	56	75.60
Substance Use Disorder	15	20.20
Antisocial Personality Disorder	10	13.50
Schizophrenia	4	5.40
Other Psychotic Disorder	7	9.40
Post-Traumatic Stress Disorder	2	2.70
Anxiety Disorder	1	1.30
Depressive Disorder	7	9.40
Restored	62	83.70
Not Restorable	12	16.30
Length of Hospitalization (Days)	74		281.64 (322.67)
Length of Hospitalization (Restored)	62		244.82 (199.96)
Length of Hospitalization (Not Restorable)	12		472.81 (681.85)

IQ scores were collected from reports that documented the total score from a standardized, individual intelligence test. There was variation in when the IQ tests were conducted (i.e., prior to or during the hospitalization for competency restoration) and the assessments utilized. The most common assessments included Wechsler Adult Intelligence Scales and Stanford-Binet Intelligence Scales (Roid & Pomplun, 2012; Wechsler, 2008). Notably, some individuals had multiple IQ scores included in the report; in cases such as this, either the most recent or most consistent/representative IQ score was collected. The average IQ score for the sample was 65.38 (SD = 6.90; range = 45 to 84). All IQ scores in this sample were in the extremely low to low average range, with most participants’ scores falling in the extremely low range (73%; see Table 2).

Table 2.

IQ Score Frequencies.

Score Range	Score Descriptor	n	%
40-49	Extremely Low	1	1.35
59-59	Extremely Low	11	14.86
60-69	Extremely Low	42	56.76
70-79	Very Low	19	25.68
80-89	Low Average	1	1.35

Procedure

Archival data were utilized to answer the proposed research questions; data were obtained via patient file review after receiving Institutional Review Board (IRB) approval from both the academic institution of the investigators following a full board review and the hospital’s research committee. Risk was determined to be minimal given the archival nature of the data being extracted, and no identifiable data were removed from hospital databases or the hospital premises. Hospital staff conducted a search from medical record databases to identify individuals hospitalized for competency restoration with a diagnosis related to intellectual deficits and extracted forensic and social service reports. Six categories of variables were extracted from files by researchers: (1) demographic variables (age, sex, race), (2) criminal justice variables (current charge[s] and variables related to criminogenic risk [history of alcohol abuse, age at alleged offense, marital status]), (3) clinical variables (number of previous psychiatric hospitalizations, current diagnosis), (4) intellectual functioning variables (Full Scale IQ scores from an individual, standardized intelligence test), and (5) hospitalization outcomes (restoration outcome, length of hospitalization). Violence of the alleged offense was determined by utilizing Cormier-Lang Criminal History Scores for Nonviolent Offenses and for Violent Offenses (Quinsey et al., 2006). Additionally, a risk estimate for re-offending was calculated for each participant using an abbreviated compilation of relevant variables (per the from the Violence Risk Appraisal Guide), including the age of alleged offense, presence/absence of an alcohol abuse history, and marital status (Quinsey et al., 2006).

A researcher reviewed patient documents and extracted the above-described variables on site using a data code sheet. Following this, two independent, approved researchers reviewed the same documents to check the accuracy of data extraction as an inter-rater reliability check. Data were dummy-coded for categorical variables. Data entry errors were reduced by incorporating a double data entry process, comparing data entry, and correcting for errors. The data were also reviewed for any missing data. No categorical data were missing in the data set. Several participants (n = 10; 13%) were missing continuous data (i.e., number of prior hospitalizations, hospitalization length), which was 1.2% of the total dataset. Mean substitution can be effective for item-level missing data when the amount of data missing is low, as it was in this sample (Parent, 2013). Furthermore, this technique is conservative, as it does not change the distribution of the sample (Tabachnick & Fidell, 2001). Therefore, mean substitution was utilized for missing data.

Results

Intellectual functioning

A multiple logistic regression analysis was conducted to assess the relationship between IQ score and competency restoration outcome. IQ score (B = -.04, OR = .96, p = .163) was not a statistically significant predictor of competency restoration outcome. A chi-square test of goodness-of-fit test was conducted and indicated that the proposed model does not fit the data better than the null model (χ² = [1, N = 72] = 2.03, p = .154). A multiple regression analysis was conducted to assess the relationship between IQ score and length of hospitalization for competency restoration. IQ score was not a statistically significant predictor of length of hospitalization (β = .03, p = .778). Analyses indicated that IQ score only explained 0.1% of the variance in length of hospitalization (R² = .001).

A Receiver Operating Characteristic (ROC) Curve was conducted to test what IQ score cut-off maximizes the sensitivity and specificity of correctly classifying individuals as competent to stand trial. Area under the curve was indicative of moderate predictive accuracy (AUC = .708, 95% CI = .529, .887). The point on the curve closest to maximizing sensitivity and specificity (i.e., point [0, 1] on the ROC Curve) coordinated with an IQ score of 63.5 (Sensitivity =.636, Specificity = .672, 1-Specificity = .328). This means that 63.6% of cases in which a defendant was restorable were correctly identified using the cut-off score, and 67.2% of cases in which the defendant was not restorable were correctly identified with this cut off score. Because sensitivity and specificity have an inherently inverse relationship, sensitivity was prioritized over specificity; this prioritization was made because the most unwanted legal outcome in competency restoration would be to have an individual declared restored when they are incompetent to stand trial, as this violates legal statutes and defendants’ rights.

Restoration rate and length of stay

In the current study, the sample’s rate of restoration to competency to stand trial was 83.7% (n = 62), meaning most defendants were restored to competency. Length of stay was measured as the time between the admit date for the defendant and the day they were opined restored or not restorable by the evaluator. This was chosen to represent the time it took for the defendant to “complete” their treatment rather than their time at the hospital (which can be artificially lengthened by, for example, legal matters, availability of transportation, or availability of cell space at the returning facility). The average length of stay was 281.64 days (SD = 322.67), with an average of 244.83 days (SD = 199.96) for those restored, and 472.81 days (SD = 681.85) for those not restored.

Demographic variables

Given our hypothesis of a nonsignificant relationship between demographic variables and outcomes, we complied with Frick’s (1995) recommendations for such circumstances, including the criteria of using a more stringent cut-off level to determine significance (p < 0.20), as well as including other indicators of significance (i.e., effect sizes, odds ratios, Bayes factor).

First, a multiple logistic regression analysis was conducted to assess the relationship between demographic factors and competency restoration outcome. Age (B = .02, OR = 1.02, p = .44), sex (B = .22, OR = 1.24, p = .85), and race (B₁ = -.53, OR = .59, p = .48; B₂ = 19.33, OR = 2.48, p = 1.00; B₃ = 19.19, OR = 2.16, p = 1.00) were not statistically significant predictors of competency restoration outcome based on the traditional level of significance (p < .05) and the more stringent cut-off levels (p < .20, Frick, 1995). Odds ratios for each variable were also low (i.e., OR < 1 for age and sex, OR < 2 for race). A chi-square test of goodness-of-fit test was conducted and indicated that the proposed model does not fit the data better than the null model, (χ² = [5, N = 72] = 1.95, p = .856). These results support the study’s hypothesis that demographic factors are not related to competency restoration outcomes.

A multiple regression analysis was conducted to assess the relationship between demographic factors and length of hospitalization for competency restoration. Age (β = -.12, p = .37), sex (β = -.14, p = .254), and race (β₁ = -.06, p = .636; β₂ = -.18, p = .139; β₃ = -.05, p = .708) were not statistically significant predictors of length of hospitalization based on the traditional level of significance (p < .05) and more stringent cut-off levels (p < .20; Frick, 1995). Correlations between demographic variables and length of hospitalization were small (Age Pearson r = -.09; Sex Pearson r = -.12; Race_Black Pearson r = .01; Race_{White/Hispanic} Pearson r = -.16; Race_Biracial Pearson r = -.02). Additionally, effect sizes suggested a small effect for the relationship between these variables and length of hospitalization (R² = .06; Bayes factor = 5.51). Collectively, these results support the hypothesis that these demographic factors are not related to length of hospitalization.

Criminal justice variables

A multiple logistic regression analysis was conducted to assess the relationship between criminal justice involvement variables and competency restoration outcome. Violence of the alleged offense (B = -.80, OR = .45, p = .351), sexual nature of the alleged offense (B = .28, OR = 1.33, p = .857), and the three-item estimated risk score (B = -.20, OR = .82, p = .126) were not statistically significant predictors of competency restoration outcome. A chi-square test of goodness-of-fit test was conducted and indicated that the proposed model does not fit the data better than the null model, (χ² = [3, N = 72] = 3.47, p = .453).

A multiple regression was conducted to assess the relationship between criminal justice involvement variables and length of hospitalization for competency restoration. Violence of the alleged offense was a statistically significant predictor for length of hospitalization (β = -.43, p = .001), indicating that individuals who were charged with a violent offense were likely to be hospitalized for shorter periods of time than individuals charged with nonviolent offenses. Violence of the alleged offense explained 14% of the variance in length of hospitalization when added to the regression equation (sr² =.14; pr² = .140).

Sexual nature of the alleged offense (β = -.21, p = .116) and score on the three-item risk estimate for re-offending (β = .11, p = .343) were not statistically significant predictors of length of hospitalization. The optimal linear combination of all three criminal justice involvement variables was able to explain 15% of the variance of length of hospitalization (R² = .15). Therefore, these analyses partially supported our hypothesis, as violence of the alleged offense was a statistically significant predictor of length of hospitalization, but not in the predicted direction.

Clinical variables

A multiple logistic regression was conducted to assess the relationship between clinical variables and competency restoration outcome. Number of prior hospitalizations (B = .03, OR = .97, p = .834) and comorbid diagnosis (B = .51, OR = 3.69, p = .243) were not statistically significant predictors of competency restoration outcome. A chi-square test of goodness-of-fit test was conducted and indicated that the proposed model does not fit the data better than the null model, (χ² =[2, N = 72] = 1.77, p = .414).

A multiple regression was conducted to assess the relationship between clinical variables and length of hospitalization for competency restoration. Number of prior hospitalizations (β = .01, p = .998) and comorbid diagnosis (β = -.08, p = .534) were not statistically significant predictors of length of hospitalization. Analyses indicated that the optimal linear combination of clinical variables was only able to account for 0.6% of the variance in length of hospitalization (R² = .006).

Discussion

The current study examined competency restoration outcomes for defendants with a diagnosis related to intellectual deficits and identified a potential cut-off IQ score to use in predicting restoration. Understanding the interplay of factors that influence the course of competency restoration for defendants is important, given the potential impact on due process, confinement of individuals not yet convicted of a crime, as well as the significant financial costs associated with such legal determinations. Defendants with intellectual deficits present a unique situation for restoration, as these deficits are typically static and do not improve with traditional mental health treatment approaches (e.g., counseling, psychotropic medication). Understanding how to differentiate defendants with intellectual deficits who are able to be restored to competency to stand trial from those who are not restorable will not only improve competency evaluations, but ultimately contribute to a more efficacious and just legal process.

In this sample of 74 males and females with diagnoses related to intellectual deficits who completed competency restoration at a state hospital, the rate of restoration to competency to stand trial was 83.7%. This estimate is similar to rates observed in prior research for defendants without intellectual deficits, which range from 75% to 90% (e.g., Colwell & Gianesini, 2011; Morris & DeYoung, 2012; Morris & Parker, 2008; Mossman, 2007; Mowbray, 1979; Pinals, 2005; Scott, 2003; Zapf & Roesch, 2011). Though studies have found an association between intellectual deficits and evaluator opinions that defendants are not restorable (e.g., Colwell & Gianesini, 2011; Mossman, 2007; Wolber, 2008), data from this sample indicates that caution is needed with assumptions that intellectual deficits are indicative of poorer restoration outcomes. Because courts and attorneys often operate with such an assumption, providing education and identifying individualized factors for restorability is important. Given that we know evaluators’ decision-making is susceptible to their own biases about evaluees’ identities, IQ status is one such status that evaluators should track and be mindful of in order to reduce any bias in opinions. Moreover, evaluators can operate with such biases that would subconsciously influence their psychological opinions and defendant outcomes (Neal & Brodsky, 2016). Therefore, providing education to evaluators and empirically supported guidance regarding individualized factors for restorability is important.

Defendants who were restored to competency had an average length of stay of 244 days, which is consistent with average lengths of competency restoration stays for defendants without intellectual deficits (Heilbrun et al., 2019; Pirelli & Zapf, 2020). Individuals who were not restorable were hospitalized for approximately 200 days longer on average. Of note, we do not know if defendants’ length of stay was more or less of what they could have been sentenced to for their charges, as this information was not available. However, defendants at this location were facing primarily higher-level felonies, which typically included potential sentences of several years, and time hospitalized for restoration often could count as “timed served” for part of any future sentences. Finally, there is a large standard deviation for this sample’s length of stay. This shows that length of stay is highly variable for this sample, which reflects the importance of examining individual-level information when making competency restoration determinations.

Through ROC Curve analyses, we identified a preliminary cut-off IQ score of 63.5 that maximizes sensitivity and specificity. Area under the Curve (AUC) for the ROC Curve indicated moderate predictive ability of restoration. This cut-off score is consistent with prior research about the level of functioning to attain competency (Baroff, 1996; Daniel & Menninger, 1983). This finding does not support the use of an absolute IQ cutoff score for competency restoration determinations, but this information can be part of a broader set of considerations for forensic evaluator’s decision-making. While it can be viewed as reductionistic to reduce classification to an IQ score, it is important for evaluators to utilize empirical evidence in their decision making, and this cut-off score provides additional information in the larger context of the information available. From this score, evaluators can also consider that individuals with mild intellectual deficits (as measured by diagnostic categories in the DSM; American Psychiatric Association, 2022) have a greater potential to restore than individuals with moderate, severe, and profound deficits.

The current study found that the study’s demographic variables were not statistically related to competency restoration outcomes, which is consistent with prior research (Colwell & Gianesini, 2011; Nicholson et al., 1994). This is a positive finding, as demographic variables relating to restoration outcomes could indicate systemic bias in decision making. In addition, results indicated that defendants charged with a violent crime were more likely to be hospitalized for shorter periods of time. Although specific information about defendants’ cases was not available, some possibilities to explain this finding include: 1) these cases could involve more concrete evidence (e.g., witness testimony, video capture, weapons discovered at the scene) and require lower necessary cognitive sophistication and abilities, 2) there is greater emphasis on restoring criminal defendants accused of violent crimes (i.e., a tendency to rush to justice) compared to defendants accused of non-violent crimes, 3) there is more focused pressure and scrutiny on such cases from the courts and therefore restoration staff and evaluators are more focused on such defendants, or 4) examiners unintentionally lower their clinical standards or thresholds when violence is alleged (e.g., implicit bias).

Of note, IQ score was not significantly correlated with or predictive of restoration outcomes in our analyses. This is likely due, at least in part, to a small sample in the current study and comorbidity of diagnoses in the sample. However, this also highlights an important note: IQ score alone is not sufficient to determine competency to stand trial or restorability. In this sample, IQ scores of restored and not restorable defendants were similar in many cases, and in some cases, unrestorable defendants had higher IQ scores than restored defendants. Intellectual Disability and specific intellectual deficits vary from individual to individual, such that individuals with similar IQ scores may have different academic-oriented or applied abilities and life skills. Ostensibly, individuals with Intellectual Disability Disorder or impaired intellectual abilities with similar IQ scores may have varying psycholegal abilities and different case demands. Additionally, other comorbid conditions can exacerbate deficits beyond those detected by an IQ test or lead to other competency impairments. This suggests that IQ score alone is not inherently associated with psycholegal abilities, and therefore, clinicians should certainly weigh data in addition to IQ score when opining about restorability (e.g., capacity to learn new information, reasoning capacity). Therefore, some clinical implications include the consideration of utilizing cognitive screening assessments at the onset of hospitalization, and then based off such assessments, tailoring the treatment for defendants with intellectual deficits to meet their specific needs. Additionally, when evaluators are making determinations about individuals with intellectual deficits, they should consider any potential bias related to evaluees. For example, evaluators can track pertinent details for each case and their ultimate opinion for a more objective indicator of potential biases and utilize empirical data to help ground opinions.

Limitations

Several limitations exist for the current study. First and foremost, power analyses indicated that our analyses were underpowered (i.e., power < .80), except for the analyses related to determining the relationship between diagnostic comorbidity and competency restoration outcome. Furthermore, some participants were excluded from the sample based on participant criteria that had intellectual deficits (e.g., defendants diagnosed with Intellectual Disability but with no formal IQ score included in the report). This is problematic because it is unknown if there are potential reasons why some defendants were not referred for formalized testing. For example, defendants with more serious cognitive deficits may not have been referred for formalized testing, as their deficits were evident, whereas defendants with milder or potentially borderline abilities may have been more likely to be referred. Another limitation is the lack of available data on defendant’s engagement with restoration services (e.g., number of sessions attended, number of therapeutic contacts, treatment effort).

Furthermore, some limitations stem from the nature of the data. IQ scores were extracted from records, which have variable sources for IQ scores. For example, some IQ scores were from tests administered years prior to their hospitalization, whereas other IQ scores were extracted from intellectual testing administered during the hospitalization for competency restoration. Because some defendants had multiple IQ scores listed in reports, reliance on the most recent score or the score identified by the forensic examiner as most representative of the defendants’ abilities was utilized. The lack of available data on neuropsychological variables and composite index scores in IQ testing is another limitation. Additionally, competency restoration outcomes were based on evaluator opinion, rather than court determination; while courts tend to agree with evaluator opinions, it is possible there was a different court finding (Gowensmith et al., 2012).

Finally, this sample was not fully representative of all defendants with intellectual deficits found incompetent to stand trial, as data were collected from a maximum-security state hospital that houses defendants with more serious felony charges or who are too aggressive for a lower security (less restrictive) hospital. Additionally, our sample was not diverse in race or gender, but was largely similar to populations in the criminal justice system. For example, 66.2% of our sample was White compared to 57.6% of the federal prison population, 29.7% of our sample was Black compared to 38.6% of the prison population, and 86.4% of our sample was male compared to 93.3% of the prison population (Federal Bureau of Prisons, 2021). Therefore, the generalizability of results obtained in this study to all defendants with intellectual deficits is limited by these constraints and confounds.

Future directions

Future research should replicate this study with a larger sample of defendants who are incompetent to proceed and diagnosed with either an Intellectual Disability or a diagnosis related intellectual deficits. Future studies should include a larger proportion of defendants who are not restorable and a sample that is more diverse in terms of gender, race, and types of charges (e.g., including both felonies and misdemeanors). Additionally, future research should examine restoration outcomes with formal court adjudications. Additional examinations of this population may also want to incorporate case complexity when looking at restoration outcomes (e.g., more specific charge classifications, types of evidence) and including examination of adaptive functioning. A long-term direction for future research is to examine competency restoration services and their efficacy for this specific population (e.g., psychoeducation programs designed specifically for defendants with intellectual deficits). Although some research has begun to do this, the intent of this study and other similar studies is to help ground competency restoration treatment planning and evaluation with empirical support.

Conclusion

The current study’s findings suggest that defendants with intellectual deficits who are incompetent to stand trial have similar restoration rates to the general group of defendants who are incompetent to stand trial. This finding is consistent with prior literature suggesting the majority of defendants with intellectual deficits adjudicated not competent to stand trial are likely to be restored. The current study found that the study’s demographic variables were generally not statistically related to competency restoration outcomes. To assist in determining whether a defendant with Intellectual Disability will be restored to competency to stand trial, the current study was the first to identify an IQ cut off score, which in the current sample was 63.5, although this cut-off score is not absolute.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Karen Grabowski

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding authors. The data are not publicly available to protect the privacy of study participants.

References

Advokat

C. D.

Guidry

Burnett

D. M. R.

Manguno-Mire

Thompson

J. W.

(2012). Competency restoration treatment: Differences between defendants declared competent or incompetent to stand trial. The Journal of the American Academy of Psychiatry and the Law, 40(1), 89–97.

American Psychiatric Association . (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev).

American Psychiatric Association . (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev).

Anderson

(1999). The effect of competency restoration training on defendants with mental retardation found not competent to proceed. Dissertation Abstract International, 59(7), 37-67.

Anderson

S. D.

Hewitt

(2002). The effect of competency restoration training on defendants with mental retardation found not competent to proceed. Law and Human Behavior, 26(3), 343-351.

Baroff

G. S.

(1996). The mentally retarded offender. In Jacobson

J. W.

Mulick

(Eds.), Manual of diagnosis and professional practice in mental retardation (311-321). American Psychological Association.

Bonnie

(1992). The competency of defendants with mental retardation to assist in their own defense. Journal of Criminal Law and Criminology, 81(3), 419-446.

Callahan

Pinals

D. A.

(2020). Challenges to reforming the competence to stand trial and competence restoration system. Psychiatric Services, 71(7), 691-697.

Carbonell

J. L.

Heilbrun

Friedman

F. L.

(1992). Predicting who will regain trial competency: Initial promise unfulfilled. Forensic Reports, 5(1), 67-76.

10.

Center for Legal Advocacy DBA Disability Law Colorado v Barnes

Marshall

, et al. (2019). Available at : https://www.scribd.com/document/404110968/Center-for-Legal-Advocacy-v-Michelle-Barnes-et-al-Consent-Decree

11.

Colwell

L. H.

Gianesini

M. A.

(2011). Demographic, criminogenic, and psychiatric factors that predict competency restoration. Journal of the American Academy of Psychiatry and Law, 39(3), 297-306.

12.

Cooper

V. G.

Zapf

P. A.

(2003). Predictor variables in competency to stand trial decisions. Law and Human Behavior, 27(4), 423-436.

13.

Daniel

A. E.

Menninger

(1983). Mentally retarded defendants: Competency and criminal responsibility. American Journal of Forensic Psychiatry, 1(4), 145-156.

14.

Everington

Notario-Smull

Horton

M. L.

(2007). Can defendants with mental retardation successfully fake their performance on a test of competence to stand trial? Behavioral Sciences and the Law, 25(4), 545-560.

15.

Federal Bureau of Prisons . (2021). Inmate Statistics. U.S. Department of Justice. https://www.bop.gov/about/statistics/statistics_inmate_gender.jsp

16.

Fett

J. M.

(2020). Relationship between adjudicated competence and cognitive functioning (Order No. 13886679). Available from ProQuest Central; ProQuest Dissertations & Theses Global; SciTech Premium Collection; Social Science Premium Collection. (2491131592).

17.

Fitch

W. L.

(2014). Forensic mental health services in the United States: 2014 (Report No. 3, HHSS2834200IT). Alexandria, VA: National Association of State Mental Health Program Directors.

18.

Frick

R. W.

(1995). Accepting the null hypothesis. Memory and Cognition, 23(1), 132-138.

19.

Gay

J. G.

Vitacco

M. J.

Ragatz

(2017). Mental health symptoms predict competency to stand trial and competency restoration success. Legal and Criminological Psychology, 22(2), 288-301.

20.

Gowensmith

W. N.

(2019). Resolution or resignation: The role of forensic mental health professionals amidst the competency services crisis. Psychology, Public Policy, and Law, 25(1), 1–14.

21.

Gowensmith

W. N.

Murrie

D. C.

Boccaccini

M. T.

(2012). Field reliability of competence to stand trial opinions: How often do evaluators agree, and what do judges decide when evaluators disagree? Law and Human Behavior, 36(2), 130–139.

22.

Grossi

L. M.

Green

Schneider

Belfi

Segal

(2018). Personality, psychiatric, and cognitive predictors of length of time for competency to stand trial restoration. International Journal of Forensic Mental Health, 17(2), 167-180.

23.

Heilbrun

Giallella

Wright

H. J

DeMatteo

Griffin

P. A.

Locklair

Desai

(2019). Treatment for restoration of competency to stand trial: Critical analysis and policy recommendations. Psychology, Public Policy, and Law, 25(4), 266-283.

24.

(1996). Assessment of retardation among mentally retarded criminal offenders: An examination of racial disparity. Journal of Criminal Justice, 24(4), 337-350.

25.

Henderson

B. B.

(1998). Relationship of psychological, demographic, and legal variables to court decisions of competency to stand trial among mentally retarded criminal defendants. Journal of Criminal Justice, 26(4), 307-320.

26.

Hubbard

K. L.

Zapf

P. A.

Ronan

K. A.

(2003). Competency restoration: An examination of the differences between defendants predicted restorable and not restorable to competency. Law and Human Behavior, 27(2), 127-139.

27.

Jackson

v. Indiana.

(1972) 406No. U.S. 715. 70-5009. Available at: https://supreme.justia.com/cases/federal/us/406/715/

28.

McCallum

MacLean

Gowensmith

W. N.

(2015). The impact of defendant ethnicity on the psycholegal opinions of forensic mental health evaluators. International Journal of Law and Psychiatry, 39, 6–12.

29.

Mehl

C. D.

(1981). The mentally retarded defendant in the criminal justice system: Determining competency to stand trial. Dissertation Abstracts International, 42(9), 2069.

30.

Melton

G. B.

Petrila

Poythress

N. G.

Slobogin

Otto

R. K.

Mossman

Condie

L. O.

(2017). Psychological evaluations for the courts: A handbook for mental health professionals and lawyers. Guilford Publications.

31.

Missouri Revised

Statutes.

(2023). § 552.020. Available at: https://revisor.mo.gov/main/OneSection.aspx?section=552.020

32.

Morris

D. R.

DeYoung

N. J.

(2012). Psycholegal abilities and restoration of competence to stand trial. Behavioral Sciences and the Law, 30(6), 710-728.

33.

Morris

D. R.

Parker

G. F.

(2008). Jackson’s Indiana: State hospital competence restoration in Indiana. Journal of the American Academy of Psychiatry and the Law, 36(4), 522-534.

34.

Morris

D. R.

Parker

G. F.

(2009). Effects of advanced age and dementia on restoration of competence to stand trial. International Journal of Law and Psychiatry, 32(3),156-160.

35.

Mosotho

N. L.

Bambo

Mkhombo

Mgidlana

Motsumi

Matlhabe

Joubert

Le Roux

H. E.

(2020). Demographic, clinical and forensic profiling of alleged offenders diagnosed with an intellectual disability. Journal of Forensic Psychology Research and Practice, 20(4), 362–376.

36.

Mossman

(2007). Predicting restorability of incompetent criminal defendants. Journal of the American Academy of Psychiatry and the Law, 35(1), 34-43.

37.

Mowbray

C. T.

(1979). A study of patients treated as incompetent to stand trial. Social Psychiatry, 14(1), 31-39.

38.

Neal

Brodsky

S. L.

(2016). Forensic psychologists’ perceptions of bias and potential correction strategies in forensic mental health evaluations. Psychology, Public Policy, and Law, 22(1), 58–76.

39.

Nicholson

R. A.

Barnard

G. W.

Robbins

Hankins

(1994). Predicting treatment outcome for incompetent defendants. Bulletin of the American Academy of Psychiatry and the Law, 22(3), 367-377.

40.

Nicholson

R. A.

Kugler

K. E.

(1991). Competent and incompetent criminal defendants: A quantitative review of comparative research. Psychological Bulletin, 109(3), 355-370.

41.

Nicholson

R. A.

McNulty

J. L.

(1992). Outcome of hospitalization for defendants found incompetent to stand trial. Behavioral Sciences & the Law, 10(3), 371-383.

42.

Parent

M. C.

(2013). Handling item-level missing data: Simpler is just as good. The Counseling Psychologist 41(4), 568-600.

43.

Pinals

(2005). Where two roads meet: Restoration of competence to stand trial from a clinical perspective. New England Journal on Criminal and Civil Confinement, 31(1), 81-108.

44.

Pirelli

Zapf

P. A.

(2020). An attempted meta-analysis of the competency restoration research: Important findings for future directions. Journal of Forensic Psychology Research and Practice, 20(2), 134-162.

45.

Porter Staats

M. L. P.

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.

46.

Roid

G. H.

Pomplun

(2012). The Stanford-Binet intelligence scales, 5th ed. In Flanagan

D. P.

Harrison

P. L.

(Eds.), Contemporary intellectual assessment: Theories, tests, and issues (249–268). The Guilford Press.

47.

Ryba

N. L.

Zapf

P. A.

(2011). The influence of psychiatric symptoms and cognitive abilities on complete-related abilities. International Journal of Forensic Mental Health, 10(1). 29-40.

48.

Quinsey

V. L.

Harris

G. T.

Rice

M. E.

Cormier

C. A.

(2006). Violent offenders: Appraising and managing risk. 2nd ed. American Psychological Association.

49.

Salekin

K. L.

Olley

J. G.

Hedge

K. A.

(2010). Offenders with intellectual disability: Characteristics, prevalence, and issues in forensic assessment. Journal of Mental Health Research in Intellectual Disabilities, 3(2), 97-116.

50.

Scott

C. L.

(2003). Commentary: A road map for research in restoration of competency to stand trial. Journal of American Academy of Psychiatry and Law, 31(1), 36-43.

51.

Tabachnick

B. G.

Fidell

(2001). Using multivariate statistics. 4th ed. Allyn & Bacon.

52.

Toofanian Ross

Padula

C. B.

Nitch

S. R.

Kinney

D. I.

(2015). Cognition and competency restoration: Using the RBANS to predict length of stay for patients deemed incompetent to stand trial. The Clinical Neuropsychologist, 29(1), 150-165.

53.

Trueblood

. Washington State Department of Social and Health Services, 101 F. Supp. 3d 1010 (W.D. Wash. 2015).

54.

Warren

J. I.

Chauhan

Kois

Dibble

(2013). Factors influencing 2,260 opinions of defendants’ restorability to adjudicative competency. Psychology, Public Policy, and Law, 19(4), 498-508.

55.

Warren

J. I.

Murrie

D. C.

Stejskal

Colwell

L. H.

Morris

Chauhan

Dietz

(2006). Opinion formation in evaluating the adjudicative competence and restorability of criminal defendants: A review of 8,000 evaluations. Behavioral Sciences and the Law, 24(2), 113-132.

56.

Warren

J. I

Rosenfeld

Fitch

W. L.

Hawk

(1997). Forensic mental health clinical evaluation: An analysis of interstate and intersystemtic differences. Law and Human Behavior, 21(4), 377-390.

57.

Wechsler

(2008). Wechsler adult intelligence scale. 4th ed. (WAIS-IV). [Database record]. APA PsycTests.

58.

Wolber

(2008). The unrestorable incompetent defendant: Length of attempted restoration and factors contributing to a decision of unrestorable. American Journal of Forensic Psychology, 26(3), 63-77.

59.

Upton

M. A.

Muschett

Kurian

James

Sherron

(2020). Determining reasonableness: Identification of the non-restorable person adjudicated incompetent to stand trial. The Journal of Forensic Psychiatry and Psychology, 31(2), 255-272.

60.

Zapf

P. A.

Roesch

(2011). Future directions in the restoration of competency to stand trial. Current Directions in Psychological Science, 20(1), 43-47.

61.

Zapf

P. A.

Roesch

Pirelli

(2014). Assessing competency to stand trial. In Weiner

I. B.

Otto

R. K.

(Eds.), The Handbook of Forensic Psychology (281-314). John Wiley & Sons, Inc.