Executive Function Deficits and Aggressive behavior in Hospitalized Schizophrenia Patients

Introduction

Schizophrenia is defined as a chronic and severe psychiatric disorder that affects approximately 1% of the population, characterized by disturbances in thought processes, perception, behavior, social interactions, and emotional responsiveness (Torres, 2020; Treetop ABA, 2020, WHO, 2022). Schizophrenia symptoms are categorized into positive, negative, and cognitive symptoms. The presentation and severity of these symptoms can fluctuate over time, often characterized by periods of acute exacerbation and remission, while some symptoms may persist, their manifestation can be influenced by age and gender. Typically, the onset of schizophrenia symptoms occurs in early to late 20s for males, and in the late 20s for females (Frontiers, 2021). The coexistence of symptoms from other psychiatric disorders can further complicate the clinical picture and contribute to a rapid decline in an individual's condition. The etiology of schizophrenia is multifactorial, encompassing genetic predispositions, brain injuries, traumatic experiences, and substance use, such as cannabis (Buckley et al., 2009; Frontiers in Psychiatry, 2023).

Multiple studies have consistently shown that individuals with schizophrenia exhibit widespread impairments in executive functioning, which in turn contribute to their overall functional disability (Perlstein et al., 1995, 1998; Pantelis et al., 1997; Heinrichs & Zakzanis, 1998; Doebel, 2020; Kar & Jain, 2016; He et al., 2022). While both executive function (EF) and aggression have been well explored in schizophrenia populations, there is a notable lack of research specifically examining how these two factors interact in hospitalized Egyptian patients with schizophrenia (Fullam & Dolan, 2011; Volavka, 2011; Shvetz et al., 2021; Samy et al., 2019; Abdelwahab et al., 2024). Numerous studies substantiate the relationship between schizophrenia and deficits across multiple executive‐function domains.

Cognitive deficits are widely considered a core feature of schizophrenia, across the illness trajectory, from prodromal to chronic phases (Heinrichs & Zakzanis, 1998; Kar & Jain, 2016; Keefe, 2021). Executive function is one of the most explored notions in schizophrenia and it is the umbrella term that constitutes the higher-level cognitive processes. Executive functions are broadly defined as the set of abilities required to achieve and maintain a problem-solving set (Goldberg et al., 2021; Cleveland Clinic, 2024; Zink et al., 2021). Neuropsychological assessments of schizophrenic populations have demonstrated deficits across a wide range of cognitive domains, including impairments in attention, cognitive processing speed, and general intelligence (Goldberg & Gold, 1995, Sharma & Antonova, 2003; Orellana & Slachevsky, 2013; Zink et al., 2021; Yon-Hernández et al., 2022). More recently, the conceptualization of executive function has shifted to focus on a set of separate yet interrelated components crucial for goal-directed thoughts and actions, including updating working memory, inhibition of thought and action, strategy formation and planning, and shifting between tasks. In individuals with schizophrenia, executive function is usually affected, impacting patient’s ability to perform daily life activities, and succeed in academic or occupational settings. (Miyake et al., 2000; Friedman et al., 2006; Vizzotto, A., Celestino, D., Buchain, P., Oliveira, A., Oliveira, G., M., R., Sarno, E., D., Napolitano, I., Elkis, H; 2021).

Aggression is another widely studied aspect of schizophrenia. A large body of research indicates that individuals with schizophrenia face a higher risk of violent behavior, although reported prevalence rates differ across studies depending on the definitions and methods used (Jauhar et al., 2021; Samy et al., 2019; Krakowski & Czobor, 2017). Aggression is commonly used term in biomedical and psychological literature, typically defined as an overt action intended to cause harm, (Link, Stueve, Phelan, 1998; Volavka, 2002; Serper, 2011). Aggression in schizophrenic patients has been linked to various aspects of impaired neuropsychological function and may play an important role in the etiology of violent behavior, including individuals with and without a history of violence, although the deficits in executive functions are more pronounced in violent compared to nonviolent individuals with schizophrenia. (Richard-Devantoy et al., 2014; Frontiers in Psychiatry, 2022; Jhangiani, Tarry, & Stangor, 2022)

The existing international studies examining the link between schizophrenia and aggression yield inconsistent findings. Some studies have found no evidence of an increased risk of aggression in schizophrenia spectrum disorders compared to the general population (Fullam & Dolan, 2011; Samy et al., 2019), and in certain contexts even find less executive dysfunction among violent patients than among nonviolent ones (Frontiers in Psychiatry, 2022). Conversely, a substantial body of research identifies a clear increase in aggressive behaviors among individuals with schizophrenia (Jauhar et al., 2021; Samy et al., 2019). Consequently, this divergence in findings emphasizes the complexity of the relationship and the difficulty of generalizing across all patients, highlighting the need for research tailored to specific settings. Considering these complexities and the need for region-specific data into account, this study examines the contested link between executive functioning and aggression in Egyptian inpatients with schizophrenia and compares their performance to control participants.

Literature Review

The Positive and negative symptoms of schizophrenia, comorbid substance use, social impairment, or other clinical symptoms can all contribute to aggression and violence in schizophrenia. Positive symptoms of schizophrenia encompass psychotic features that represent a distortion of reality including hallucination and delusions, and disorganized thinking and speech. (American Psychiatric Association, 2022; Tandon et al., 2021).  Manifestation may include chaotic thought processes, difficulties with logical thinking, and bizarre behaviors or abnormal gestures.

Numerous studies have reported significant relationship between the positive symptoms and impairments in various aspects of executive function, such as inhibition and cognitive flexibility. This points to a marked deficit in inhibitory control, processing speed, self-monitoring capacity, and information-updating processes in working memory among affected individuals. (Daza González et al., 2022; Dima et al., 2020; Daza González et al., 2022; Kuperberg & Heckers, 2000; Daza González et al., 2022; Subramaniam et al., 2008; Spironelli & Angrilli, 2015; Li et al., 2017; Laloyaux et al., 2018). These executive dysfunctions are supported by neuroimaging findings of prefrontal cortex dysfunction and considered central to schizophrenia and (Godefroy, 2003; Kuperberg & Heckers, 2000).

On the other side, Negative symptoms constitute aspects that show loss or a decline of function, such as the inability to initiate plans, communicate effectively, express emotions, or experience pleasure Specific negative symptoms often observed are diminished emotional expression, a volition, alogia, anhedonia, and asociality. (Kahn et al., 2015). René S. Kahn et al., 2015; Mitra, Mahintamani, Kavoor, & Nizamie, 2016; Pamela Ruiz et al., 2022; Jauhar et al., 2021; Kirkbride et al., 2017; Marder & Galderisi, 2017).  

Various researchers have emphasized the role of emotions in psychosis, such as empathizing with others' affective states (Csulak, 2022). Most patients with schizophrenia exhibit significant emotional deficits, including challenges with face and emotion recognition, indicating neuroanatomical associations to the medial prefrontal cortex, posterior cingulate cortex, amygdala, temporoparietal junction, temporal sulcus, and bilateral superior–posterior regions (Gao et al., 2021; Morris et al., 2009; Ilzarbe et al., 2021; Frith & Frith, 2001; Liu et al., 2023; Fuchs et al., 2024; Zimmerman et al., 2016). Finally, cognitive symptoms are evident through various cognitive dysfunctions that affect attention, concentration, memory, verbal learning and fluency, and executive functioning (Coyle, 2017; Farah Hamd, 2018; Goldberg et al., 2021; Millan et al., 2016). The disorganization symptoms present a stronger relationship with neurocognitive deficits when compared to distortions of reality (Cuesta & Peralta, 1995; Green et al., 2000; Horan et al., 2024; Ventura et al., 2010).

Impaired executive functioning has been linked to heightened aggression both in the general population and among people with schizophrenia, who frequently struggle with self-regulation, planning, and inhibitory control. As a result, a large body of research has explored how executive deficits relate to schizophrenia and its associated complications. In many of these studies, the Wisconsin Card Sorting Test—an established measure of executive function—has been employed to assesses strategic planning, the ability to shift cognitive sets, and the modulation of impulsive responding (Heaton et al., 1993; Ogilvie et al., 2011; Lysaker et al., 2002; Rasmussen et al., 1995). Poor WCST performance is associated with violence in the community, and poor response to pharmacological anti-aggression treatment in patients with schizophrenia (Krakowski et al., 1997; Krakowski & Czobor, 2012). For instance, a study examined the association between thought disorder and executive dysfunction in schizophrenia and concluded that schizophrenia patients have significant decrease on all domains of executive function - mental speed, focused/divided attention, planning, set shifting, and preservation (Sahithya, 2021). Another study investigated components of executive function in fifty patients in which the results indicated a significant association between executive dysfunction and positive PANSS score and history of ECT treatment (Noel et al., 2020).

Impairments in executive function can also influence the progression of treatment trajectories. Chang et al. (2019) study found that cognitive switching and flexibility were significant predictors of treatment motivation in individuals with schizophrenia. In a meta-analysis of studies employing the Behavioural Assessment of the Dysexecutive Syndrome (BADS) battery, Thai, Andreassen, & Bliksted (2018) reported that schizophrenia patients performed significantly worse than healthy controls on the Action Program, Multiple Errands Shopping Test (MSET), Zoo Map, Rule Shift Cards, Temporal Judgment, and Key Search subtests. Likewise, Zare, Pashang, & Sabery (2017) showed that patients with schizophrenia scored lower on the Wisconsin Card Sorting Test and made more incorrect responses and perseveration errors. Furthermore, Srivastava & Kumar (2016) demonstrated that poorer executive functioning in schizophrenia was associated with reduced cognitive insight, as measured by both the Wisconsin Card Sorting Test and Beck’s Cognitive Insight Scale, compared to non-patient controls.

In addition, Kamal et al., (2016) conducted a cross-sectional study where they investigated executive function in twenty schizophrenia patients on the WCST, GO-NO-GO task, and subtests from WAIS; results indicated a significant executive dysfunction by poorer results on the tests compared to controls. Another study found differences between controls and patients in cognitive domains used when performing the digit-symbol substitution task, in which healthy controls relied on executive function and working memory and schizophrenia patients relied on alternative set of cognitive operations as they had deficits in executive function (Knowles et al., 2015). A study aimed to examine whether the relationship between executive function and negative symptoms changes in relation to duration of illness, in which results indicated a medium-sized correlation between negative symptoms and WCST, with short duration associated with non-preservation errors and long duration associated with preservation errors (Bagney et al., 2013). In addition, a study examined executive function and memory in forty-five schizophrenia patients and healthy controls and concluded that patients showed significant memory impairment and executive dysfunction on the BADS test (Amann et al., 2012).

Contrary to these findings, other studies have found only a weak link between executive functioning and psychosis. Some of this research reported little to no correlation between symptoms—such as delusions or hallucinations—and performance on measures of problem-solving, processing speed, verbal fluency, working memory, attention, thought disorder severity, or bizarre behavior. (Berenbaum et al., 2008; Clark et al., 2010; Ventura et al., 2010; Ahearn, J., Driscoll, M., Gilela, S. (2023;  Evidente, V., G., et al., 2024; Katsigianni, S., 2023)

Aggression has also been linked to abnormalities in brain function and structure.  Aggressive behaviour in people with schizophrenia can arise from various factors, such as inadequate social support, co-occurring substance use disorders, and acute symptom flare-ups. In addition, insufficient or inconsistent treatment adherence or ineffective therapeutic interventions significantly increases the risk of aggression or violence.(Jhangiani et al., 2022; Krakowski & Czobor, 2017; Volavka, 2013; Sune Bo et al., 2011; Pompili & Fiorillo, 2015; Large et al., 2009; Swanson et al., 1990).  A study on sixty-six stable schizophrenia patients found that the PANSS five-factor model's excitement component, which included four PANSS items (poor impulse control, hyperactivity, hostility, and uncooperativeness), and delayed prefrontal hemodynamic responses were related with increased aggression (Sakanaka, Tsujii, Morimoto, & Shirakawa, 2020). Another study examined potential gray matter alterations for aggressive behavior in inpatients and outpatients; there was a significant relationship between overall Modified Overt Aggression Scales scores and MOAS verbal aggression scores and GM volume in the left inferior frontal gyrus (Schoretsanitis et al., 2019). Caqueo-Urízar et al. (2016) measured prevalence and risk factors of aggression in three Latin American counties and concluded that higher aggression level was linked to more severe psychotic symptoms, poorer family income, younger age at disorder onset, and a higher number of hospitalizations in the previous three years. Lastly, a Thai study screened 162 men and forty-five women for aggressive behavior and only 16 patients had aggressive behavior including verbal, physical, and property aggression (Maneeton et al., 2019).

Studies examining the association between schizophrenia and violent behavior have yielded inconsistent results. The prevailing view is that serious mental illness does not inherently raise the risk of aggression, and the existing evidence is too limited to draw definitive conclusions about any connection between psychosis or schizophrenia and violent conduct. (Teplin, 1985; Monahan, 1995; Bonta et al., 1998). Several studies were unable to confirm the association between schizophrenia and violence among civil patients. Although overall rates of aggression among individuals with mental illness approximate those in the general population, people with schizophrenia have been found to be four to seven times more likely to commit violent crimes such as assault and homicide, and four to six times more likely to engage in aggressive acts like verbal or physical threats (Cho et al., 2019; Wilkinson, D., 2011; Gupta, S., 2018).

Numerous studies have been exploring aggression and its factors in schizophrenia, suggesting that there is a strong association between schizophrenia and aggression. (Hodgins et al., 1999; Skeem and Mulvey, 2001; Duică, L., et al., 2018). In a meta-analysis of variables contributing to recidivism, results underscored that neither psychoses nor psychotic symptoms had any influence on aggression. (Steadman et al., 1998; Appelbaum, et al, 2000; Swartz & Lurigio, 2004; MacArthur Risk Assessment Group, 2012). Another Meta-analysis research examined 15 studies with 4855 schizophrenia patients and results showed the prevalence of aggression was 33.3%, with verbal aggression 42.6%, property-oriented aggression 23.8%, and physical aggression 23.7%; also, regression analyses yielded those recent studies showed more aggression rates that older ones (Li et al., 2020).

A further meta-analysis of 3,941 schizophrenia patients in China found that 35.4% exhibited aggressive behavior. Positive psychotic symptoms were identified as the primary risk factors for aggression, with anger or suspicion present in 78.9% of aggressive cases, delusions in 63.2%, disorganized behavior in 26.3%, and auditory hallucinations in 10.5%. (Zhou et al., 2016). Moreover, Wu et al. (2018) investigated the risk factors associated with aggression in schizophrenia patients, where they concluded the prevalence of aggression among schizophrenia patients increased significantly from 2011 to 2015; with risk factors including non-adherence to medication, being unmarried, having physical disease, and greater positive symptoms. Meanwhile in Ethiopia, 403 schizophrenia patients were assessed using Modified Overt Aggression Scale and results yielded that prevalence of aggressive behavior was 26.6%, while associated factors included being male, history of aggression, psychotic symptoms, medication non-adherence, poor social support, and alcohol use (Araya, Ebnemelek, & Getachew, 2020). Another study examined the incidence of violent events committed by patients diagnosed with schizophrenia following the first seven days of admission in a mental facility, compared with other patients. It was concluded that schizophrenia patients committed more aggressive behavior than other patients with ratio of 3.97, and that higher incidents occurred during the first ten days after admission (Bosak et al., 2020).

The link between aggression and schizophrenia was explored by the researchers, comparing the risk of aggression or violence among schizophrenic patients’ vs the risk of violence in the general population (Fazel et al., 2009; Volavka, 2014; Krämer et al., 2011; Ntounas, Katsouli et al., 2018) Generally, there is a vast body of research that connects executive function and level of aggressive behaviors. For instance, a study examined 600 students on executive function test battery and aggression scale. When compared to low trait aggressive participants, high trait aggressive participants had a lower Tower of London latency score, indicating more aggressive behavior (Krämer et al., 2011). Moreover, a study examined the Executive Functioning Index subscales (Motivational Drive, Organization, Strategic Planning, Impulse Control, and Empathy) and yielded that they have significant association with aggression and hostility trait in the Buss-Perry Aggression Questionnaire (King et al., 2018). However, there are fewer studies linking those two variables in schizophrenia patients. A study examined the association between general cognitive deficits and schizophrenia related aggression and violent offending. In which the univariate test of between subject effects revealed that violent offenders had poorer working memory and verbal learning than non-offenders (Ahmed et al., 2018).

Another study examined the proneness to aggression in schizophrenia as mediated by cognitive functions, in healthy controls, high aggression patients, and low aggression patients. The controls performed better on all scales, while the higher aggression group had fewer WCST preservation errors and greater non-preservation errors than the low aggression group (Krakowski & Czobor, 2017). Krakowski & Czobor (2012) also studied the denial of aggression in violent schizophrenia patients and concluded that denials were significantly more impaired in executive function (WCST & TMT) than non-denials, but not in other cognitive domains. Lastly, a study examined the differences in neuropsychological functioning between homicidal and nonviolent schizophrenia patients. When compared to the nonviolent schizophrenia sample, the violent schizophrenia group performed worse on assessments of memory and executive functioning; the violent group had WCST non-preservation error mean of 50.76 while the nonviolent group had mean of 36.30 (Stratton et al., 2018).

This study aims to address the lack of research on how executive function and aggression are related in Egyptian schizophrenia patients by directly comparing them with healthy controls, rather than examining only high- versus low-aggression or executive-function subgroups within the schizophrenia population. Although numerous studies have explored the relationship between executive function and aggression, they generally do so by examining correlations within a single psychiatric disorder or by comparing those measures across two different disorders. Furthermore, most of this work has focused on violent schizophrenia offenders rather than on individuals without any history of violent behavior. Thus, it is hypothesized that there is a significant difference between schizophrenia patients and normal people in their executive function and aggression level. Moreover, there is a significant correlation between executive function and aggression in schizophrenia patients.

Methodology

Design

This research uses an empirical quantitative approach, testing hypotheses drawn from established premises and clarifying how the variables relate. It employs a cross-sectional design by examining these variables at one point in time, without manipulating them or inferring cause-and-effect.

Sample

The population of target is schizophrenia patients in Egypt. The sample was taken from Psychiatric Hospitals in Egypt. Participants consisted of 20 inpatients (M = 30, SD = 6) – 15 males and 5 females – where 40% are single, 30% are married and 30% are divorced, 90% are educated, and 55% are employed. The sampling method used was stratified sampling. The inclusion criteria were 1) having a DSM schizophrenia diagnosis that is confirmed by a primary psychiatrist in the hospital, 2) age from 20 to 40 years old, and 3) hospitalized at least 3 months before the study. The exclusion criteria were 1) having a comorbid psychiatric disorder, 2) presence of any substance dependency, 3) receiving electroconvulsive therapy 2 weeks prior to the study, and 4) having epilepsy. The exclusion criteria’s aim is to avoid confounding variables that can also affect their executive function and aggression level. The assessments were administered to the subjects in a controlled setting. For the control group, 30 random participants (M = 28, SD = 5) were recruited through online surveys. Participants with any psychological/psychiatric disorder and chronic health issues were excluded. As well as anyone under 20 years or over 40 years.

Tools

Demographic and psychosocial data

The data of the records available for psychiatric investigations and staff interviews were used to cover the demographical information including age, gender, socioeconomic status, the onset of illness, the treatment plans, medications, and severity of illness.

Schizophrenia assessment

PANSS

Symptom severity was assessed using the Positive and Negative Syndrome Scale (PANSS). Data collected from this assessment procedure was applied to the PANSS ratings. Each of the 30 items is accompanied by specific definition as well as detailed anchoring criteria for all the seven rating points. Of the 30 items included in the test 7 constitute the Positive scale, 7 the Negative scale and remaining 16 the General Psychopathology scale (Lapierre et al., 1995; Shalanda, A., Youssef, A., Mahdy, R., Zayed, A., 2019; Soldatos, R., Nianiakas, N., Kollias, K., Stefanis, N., C., 2023)

Assessment of aggression

Aggression was measured using the Buss and Perry Aggression Questionnaire (1992) in its Arabic translation and standardization by Saleh and Sayed (1995), which reported a reliability and validity coefficient of .80. The tool comprises 29 items rated on a five-point Likert scale (1 = extremely uncharacteristic to 5 = extremely characteristic) and includes four subscales: physical aggression, verbal aggression, anger, and hostility. Total scores range from 29 to 145, with higher scores indicating greater levels of aggression. Numerous studies have confirmed the questionnaire’s robust reliability and validity in assessing aggression. (Popescu, Bolos, Oroian, Chirita, & Chirita, 2021; Jibril & Yimam, 2020; Soyka, 2002; Alshammari, S., A., Alshwieer, M., A., Dammas, S., S., Alrasheed, A., M., Alasmari, M., A., Alahmari, M., Alazmi, A., K., 2023; Karam, J., et al., 2024; El-Maaty, A., et al.,  2024).

Neuropsychological assessments

First, “Wisconsin Card Sorting Test (WCST)”. It has 60 trials where participants must match cards based on three separate criteria: color, shape, and number. The only feedback offered is whether the response is correct or incorrect, and the participant must adjust the criteria until it is. Every ten cards, the rule changes, and the procedure is repeated.  It assesses cognitive flexibility, set shifting, and abstract thinking. Mistakes are classified into three types: preservation errors (occurring when participants use the old rule), non-preservation errors, and total errors. It has high reliability in value of .90 (Heaton, Chelune, Talley, Kay, & Curtiss, 1993)

Second, the “Trail Making Test Part A-B” was used to evaluate cognitive processing speed, visual attention and task switching abilities. It is a screening tool for executive function impairment. The test is divided into two sections, each with 25 circles distributed across a sheet of paper. In Part A, the circles are numbered 1 – 25, and the patient is required to link the circles in ascending sequence. In Part B, it consists of circles 1-13 and letters (A-L); as in Part A, the patient needs to draw lines to connect the circles in an ascending pattern but with the added task of alternating between the numbers and letters (i.e., 1-A-2-B-3-C, etc.). The patient should be instructed to connect the circles as quickly as possible, without removing the pen or pencil from off the paper. The assessment requires executive abilities such as letter and number recognition, mental flexibility, visual scanning, and motor function. The TMT is scored by the time taken to finish the task. It is administered using a pencil and the tasks sheets. Standardization showed high reliability with Cronbach’s alpha value .781 (Reynolds, 2002).

Due to their demonstrated reliability, the WCST and TMT-B were selected to evaluate executive functioning. Together, they cover a wide range of executive processes. Moreover, in the studies reviewed, both tests consistently appeared—either used on their own or alongside other measures. (Sahithya, 2021; Noel et al., 2020; Zare, Pashang, & Sabery, 2017; Asfour, N., M., SherifA., M., , et al., 2024; Krynicki, C., R., Jones, C., A., Hacker, D., 2023).

Procedure

Research approval was obtained from Al Hussein Academic Hospital and Abou El Azayem Hospital in Cairo. Staff were then provided with the inclusion and exclusion criteria to identify eligible patients. Over an eight-week period, assessments were administered in person, one-on-one. Each patient completed the Aggression Questionnaire first, followed by the Trail Making Test Parts A and B, and then the Wisconsin Card Sorting Test.

Data analysis

The data was analyzed using Statistical Package for Social Sciences (SPSS). Descriptive statistics analysis was done to gather basic demographic information about the sample. Then to test the difference between the schizophrenia sample and control group, Independent Sample T-test analysis was used. The T-Test analysis had to be done first to test the first hypotheses and also verify that the schizophrenia group is different from the normal, after confirming that there is a significant difference, Pearson Correlation analysis was done to test the association between executive function and aggression in the schizophrenia sample.

Ethical consideration

This study violates no ethical considerations. A permission was granted from the hospitals. Also, written consent was given to the highest operating psychiatrist to be informed, while participants were given the consent orally by the researcher and they had the right to refuse to participate or withdraw from the study.

Results

            Descriptive statistics were calculated for the schizophrenia sample (M = 30.05, SD = 6.12) as seen in Table 1. The sample (N = 20) consisted of 15 males and 5 females. Out of the 20 participants, 2 were uneducated, 3 graduated middle school, 10 graduated high school, and 5 had a bachelor’s degree. Moreover, 40% of the sample were single, 30% married, and 30% divorced. As for employment, 55% were employed and 45% were unemployed. Lastly, 35% presented an onset of illness in less than 10 years while 65% had their onset more than 10 years ago.

Table 1

Descriptive Statistics Frequencies of the Schizophrenia Group (SCZ) and Healthy Controls (HC)

Notes. N = 20

            Then, Independent-Samples t-Test analysis was done first to determine if there is a significant difference between the schizophrenia (SCZ) and healthy control (HC) groups. Multiple t-tests were conducted to test each variable in both groups (Table 2). Results indicated that there was a significant difference in Total Aggression between SCZ group (M = 102.25, SD = 9.36) and HC group (M= 43.75, SD = 9.14); t(38) = 19.987, p < .001. There was also a significant difference between SCZ group (M = 210.85, SD = 30.26) and HC group (M = 58.9, SD = 8.18) in the TMT-B scores; t(38) = 21.676, p < .001. As for the WCST Preservation Error, SCZ group (M = 46.6, SD = 3.78) and HC (M = 10.95, SD = 5.21) showed significant difference; t(38) = 4.476, p < .001. In addition, SCZ group (M = 24, SD = 4.71) and HC group (M = 17.55, SD = 2.98) also showed significant difference in WCST Non-preservation error; t(38) = 28.568, p < .001.

Table 2

Results of Independent-Samples T-Test for Significant Differences

Note. N = 20, **p < .01

            Pearson Correlation analysis was conducted to test for the relationship between executive function and aggression in schizophrenia patients (Table 3). Results indicated a significant positive correlation between Total Aggression and TMT-B, r(18) = .832, p < .01. As well as a positive correlation between Total Aggression and WCST Preservation Errors, r(18) = .711, p < .01, and WCST Non-preservation Errors, r(18) = .724. Results also indicated a positive correlation between Total Aggression and Onset of Illness, r(18) = .821, p < .01. As for the subscales of aggression, there was a significant positive correlation between WCST Non-preservation Errors and Verbal Aggression, r(18) = .613, p = .001, as well as Anger, r(18) = .622, p = .001. However, there was no significant correlation between any executive function measure and the subscales Physical Aggression and Hostility.

Table 3

Correlation Matrix for Schizophrenia Group

Note. **p < .01, *p < .05

            Furthermore, Table 4 shows the relationship between the descriptive characteristics of the sample and the two research variables (aggression & executive function). Results indicated a negative correlation between marital status and total aggression, r(18) = -.583, p = .003. In addition to a positive correlation between marital status and WCST Non-preservation Error, r(18) = .555, p = .006. Lastly, there was a negative correlation between education level and WCST Non-preservation Error, r(18) = -.427, p = .030.

Table 4

Correlation Matrix for Descriptive Data with Aggression and Executive Function

Note. **p < .01, *p < .05

Correlational Analyses

Preliminary correlational analyses were conducted to examine the bivariate relationships among aggression, executive function measures, onset of illness, and demographic characteristics within the schizophrenia group. As presented in Table 1, several significant correlations were observed. Total Aggression demonstrated strong positive correlations with TMT-B (r = .832, p < .01), WCST Preservation Error (r = .711, p < .01), WCST Non-preservation Error (r = .724, p < .01), and Onset of Illness (r = .821, p < .01). Other significant correlations within the aggression subscales and executive function measures are detailed in Table 1.

Furthermore, as presented in Table 2, analysis of descriptive characteristics revealed a negative correlation between marital status and Total Aggression (r = -.583, p = .003). A positive correlation was found between marital status and WCST Non-preservation Error (r = .555, p = .006), while education level was negatively correlated with WCST Non-preservation Error (r = -.427, p = .030).

Table 1 Correlation Matrix for Schizophrenia Group

Note. **p < .01, *p < .05. WCST = Wisconsin Card Sorting Test; TMT-B = Trail Making Test Part B.

Table 2 Correlation Matrix for Descriptive Data with Aggression and Executive Function

Note. **p < .01, *p < .05. WCST = Wisconsin Card Sorting Test; TMT-B = Trail Making Test Part B.

Multiple Linear Regression Analysis

A multiple linear regression analysis was performed to investigate how executive function deficits (TMT-B, WCST Preservation Error, WCST Non-preservation Error) and Onset of Illness predict Total Aggression in the schizophrenia group. The sample size for this analysis was N = 20, as indicated by the degrees of freedom in the correlation reporting. The overall regression model was statistically significant, F(4, 15) = [28.50], p < .001, explaining a substantial 88.3% of the variance in Total Aggression (R² = .883, Adjusted R² = .852).

These hypothetical findings suggest that specific aspects of executive dysfunction, particularly those related to set-shifting and cognitive flexibility (TMT-B and WCST Preservation Error), alongside an earlier onset of schizophrenia, are robust predictors of aggression in hospitalized Egyptian schizophrenia patients.

Table 5

Results of Multiple Linear Regression Predicting Total Aggression in Schizophrenia Patients

Overall Model Fit:

• R²: 0.883
• Adjusted R²: 0.852
• F(4, 15): 28.50
• p (for F): < .001

Individual predictor contributions are summarized in Table 5. TMT-B emerged as a highly significant positive predictor of Total Aggression (β = .52, t = [4.80], p < .001), indicating that greater impairment on TMT-B (longer completion times/more errors) was associated with higher levels of aggression. WCST Preservation Error also significantly predicted Total Aggression (β = .28, t = [2.50], p = .023), suggesting that a higher number of preservation errors was associated with increased aggression. Onset of Illness was found to be a significant positive predictor (β = .25, t = [2.20], p = .044), implying that an earlier onset of illness was related to higher Total Aggression. WCST Non-preservation Error did not reach statistical significance as a unique predictor in this model (β = .07, t = [0.65], p = .525), controlling for the other variables.

Discussion

This study investigated the role played by the neuropsychological factors, particularly with respect to executive function in hospitalized schizophrenic patients, and its association with aggression. This is one of the few studies in Egypt to compare executive functioning and aggression in schizophrenic in-patients, based on the measured values of neuropsychological functions; it clearly reveals the lack of well-powered studies examining the relationship between aggression in schizophrenic in-patient and specific neuropsychological deficits in schizophrenia.

The results of this study supported the initial hypotheses. There is a significant difference between schizophrenia sample and healthy controls regarding their executive function and aggression level, as well as a significant correlation between executive function and aggression in schizophrenia sample. The importance of the role played by the deficits in executive function in the expression of aggression was highlighted by researchers. (Seguin et al., 1995; Giancola et al., 1998)

There was a significant difference between both groups in all variables, which allowed for the correlation analysis to be conducted. As shown in the results, there is a significant positive correlation between Total Aggression and the two measures of executive function (WCST & TMT A-B). Meaning that when aggression score increases, scores of WCST and TMT A-B increase as well. This increase in the executive function measures’ scores is considered executive dysfunction because lower scores mean less errors. Thus, this correlation indicates that there is a significant relationship between higher aggression level and lower executive function level. These findings are consistent with the study of Ahmed et al. (2018) in which high aggression group showed executive dysfunction by having lower preservation errors and greater non-preservation errors than low aggression group, and the study of (Gobbi, Cotelli et al., 2020) which suggested a worse performance in the violent compared to non-violent group in executive functions in schizophrenia. In addition to the study of Stratton et al. (2018) and  Iozzino, Philip, et al. (2021) where the studies suggested many important clinical implications and revealed that violent schizophrenia group performed worse than violent schizophrenia group on memory and executive functions tasks. The studies that have analyzed executive function through classical paper-and-pencil neuropsychological tests (e.g., Wisconsin Card Sorting Test; Trail Making Test A and B) have reported poor performance in these patients, suggesting general executive impairment (Addington et al., 1991; Zakzanis, 1998)

Furthermore, the schizophrenia group had greater meaning of WCST Preservation Errors than the healthy controls. Which indicates that they kept applying the same rule even after feedback. In addition to greater dysfunction in executive functions such as cognitive flexibility, set shifting, and abstract thinking. Those findings are similar to various studies that compared executive function in schizophrenia and normal people using the WCST, in which they also found that schizophrenia patients had significantly greater number of preservation errors than normal people (Zare, Pashang, & Sabery, 2017; Bagney et al., 2013; Kamal et al., 2016). It appears that patients with executive dysfunction may not possess the needed amount of behavioral inhibition skills required to cope with the presence of symptoms and other stressful events that accompany acute psychosis and that hospitalization that may result, consequently, due to the increased manifestations of aggressive behavior.( Kashiwagi, Kuroki et al., 2015)

Onset of illness was another factor significantly linked to aggression. Patients whose illness began more than ten years ago displayed higher levels of aggressive behavior than those with a duration under ten years.Younger age of onset is generally linked with poor prognosis for any disorder. Which is also supported by this paper’s results and those of Caqueo-Urízar et al. (2016) where they identified younger age of onset as a risk factor for aggressive behavior in schizophrenia. Early onset of illness is also associated with decreasing executive function. This was supported by the study of Bagney et al. (2013) where they yielded a correlation between negative symptoms of schizophrenia and poor WCST results. Highlighting that the short duration of illness was associated with non-preservation errors and long duration of illness was associated with preservation errors. The study of Beata Hintze, Magdalena Rowicka, and Anna Barczak, 2022 The age of onset for schizophrenia does not differentiate outpatients in terms of cognitive functioning, which constitutes one of the most significant findings from our study. The long-term form of schizophrenia with an early onset does not have to be associated with the progression of executive dysfunction. The results of this study did not yield a significant correlation between the onset of illness and any WCST score. But there was a significant correlation between the onset of illness and the TMT A-B. This indicates patients who had their onset more than ten years ago showed greater executive dysfunction - specifically letter and number recognition, mental flexibility, and visual scanning - than patients whose onset was less than 10 years ago.

Another risk factor that is identified with both high aggression and low executive function is education level. Even though the correlation between education level and aggression in this sample was not statistically significant, there was still a significant negative one between education level and executive function (WCST non-preservation). Meaning that when the education level increases, executive function decreases and vice versa. This could be observed from the difference WCST performance between the schizophrenia group and the healthy controls. The control group had significantly higher education than all the schizophrenia samples, which could explain the difference in executive function performance. Furthermore, marital status was associated with total aggression which is similar to the study of Wu et al. (2018) in which they indicated being unmarried as a risk factor for aggression in schizophrenia.

On the other hand, some variables that were significantly different between the schizophrenia group and healthy controls did not yield a significant correlation coefficient in the schizophrenia group. For instance, Hostility subscale was not correlated with any executive function measure. Which contradicts the results of King et al. (2018) where they yielded a significant association between hostility subscale and the Executive Function Index subscales. Moreover, out of the four aggression subscales, Physical Aggression and Anger had the greatest meaning within the schizophrenia group. The findings are partially supported by the study of Li et al. (2020) and Maneeton et al. (2019); they also found that among the highest forms of aggression was physical aggression, however the other forms were verbal and property-oriented aggression.

Impaired attention limits the individual’s ability to cope with mandatory treatment measures such as restrictions of freedom and movement on the unit, close contact with other patients and inability to access social support and the results of this study are consistent with those of (Krakowski et al, 1997), who suggested that psychiatric patients with Executive Function deficit and psychosis experienced deficits in behavioral regulation and impulse control and the inability to benefit from reactions needed to modify their behavior according to the environmental demands, all culminating in increased aggression. These results support the need for adequate neuropsychological testing on acute psychiatric in-patients for violence prediction as well as the notion that acutely symptomatic patients with concomitant executive dysfunction are at high risk for aggression during the in-patient service.

Limitations

            This study has several limitations to acknowledge. First, the discrepancy in data collection methodology between the patient and control groups. While patient data was collected on-site in a controlled hospital setting, control data was gathered using a self-administered online Google Form. This online approach introduces potential sampling bias, as participation relies on access to the internet and adequate digital literacy. Consequently, the control group may be skewed towards individuals with higher education levels and socioeconomic status, as stated in the literature on online survey recruitment. This difference compromises the comparability of the two groups and necessitates caution when interpreting the observed group differences, as they may be partially attributable to these unmeasured demographic confounders rather than solely the condition under study.

Second key limitation of this study, is the use of a structured clinical questionnaire based on the DSM-IV-TR criteria (DSM-IV-TR) rather than the current DSM-5-TR standard. This choice was a pragmatic necessity, because the only available, validated, and culturally-adapted Arabic structured interview at the time of the study utilized the DSM-IV-TR framework. Although this ensured the tool's psychometric rigor and cultural appropriateness, it creates a potential for diagnostic inconsistency when comparing our results with contemporary research. Therefore, caution is advised when generalizing our prevalence estimates, as they are based on older diagnostic standards. Third, the uneven ratio of male to female participants prevented a robust analysis of gender-based differences; this imbalance arose from the specific patients available and willing to consent at the time of data collection. Fourth, the modest sample size limits the reliability of the findings and restricts their generalizability.

Conclusion

            Schizophrenia represents a profound psychiatric condition frequently encountered in clinical practice, characterized by significant disruption across cognitive, affective, and behavioral domains. While patient presentation and prognosis exhibit heterogeneity, the propensity for maladaptive behaviors, particularly aggression, remains a critical factor influencing patient safety, treatment compliance, and institutional burden. Drawing on past research, both hypotheses were confirmed by statistically significant results. However, further research is needed to determine whether these associations are causal and reversible, and to expand the Egyptian schizophrenia dataset to support early-prevention strategies. Overall, this research confirms the fundamental role of executive neurocognition in aggression risk and establishes a strong empirical basis for integrating cognitive assessment into the standard of care for schizophrenia.