Parricide and homicide NGRI offenders: How do they differ?

Abstract

The aim of the present study was to provide a forensic psychiatric characterization of perpetrators of parricide who were found not guilty by reason of insanity (NGRI). We conducted a study involving 52 NGRI patients who had committed homicide or attempted homicide within the Department of Forensic Psychiatry in Thessaloniki, Greece, between January 2015 and 2020. Subjects were categorized into two groups: parricide (n = 21) and a control group (n = 31). Our findings revealed that in the parricide group, the majority of patients were unmarried males in their thirties, with a history of prior contact with mental health services and nonadherence to treatment. Additionally, they had a background of substance abuse and exhibited violent behavior before the index crime. A notable trend observed among parricide offenders was the tendency to seek hospitalization, possibly as a means of distancing themselves from stressful family environments, based on information obtained in the interviews conducted as a part of this research. All instances of parricide involved the use of sharp weapons, and the crimes were consistently committed in private settings. Symptomatology among parricide patients was assessed as moderate to severe, with a significant long-term risk observed following the crime. The primary differences identified between the two groups were the higher pre-crime voluntary admissions and the elevated estimated postcrime risk observed in the parricide group. Early intervention, comprehensive assessment of risk factors, family support, and assistance in resolving conflicts and reintegrating patients into society are emphasized as critical interventions that can potentially prevent future tragedies.

Keywords

Parricide mentally ill offenders homicide matricide postcrime risk

Introduction

Parricide refers to the homicide of a parent committed by their offspring,¹ encompassing both biological and adoptive parents.² This category constitutes 2–4% of all homicides globally.^3,4 Despite its infrequency, parricide garners considerable media attention and public interest due to its violation of a deeply intimate familial bond, sparking scholarly curiosity within the scientific community.

The study of parricide offenders typically distinguishes between juvenile and adult perpetrators. Juveniles often report higher rates of parental abuse, whereas the majority of adult offenders exhibit significant mental disorders, most commonly schizophrenia.^1,5 Adult offenders outnumber juveniles statistically.^6,7 In earlier literature, parricide offenders were categorized into three primary types⁸: (a) severely abused children, (b) severely mentally ill children, and (c) dangerously antisocial children. Subsequently, Heide identified a fourth type characterized by long-standing conflict, often involving substance intoxication and a history of child abuse.⁹ Establishing distinctions among perpetrator types is crucial for understanding and addressing this phenomenon within the social sciences, guiding theoretical and practical approaches.¹⁰

Heide's comprehensive study of diverse parricide offenders revealed psychiatric disorders across all offender categories. Major depression was notably prevalent among severely abused perpetrators, while psychopathy was associated with dangerously antisocial behavior. Notably, mental illness was identified as a direct factor in perpetrating homicide primarily among severely mentally ill offenders. According to Nordström and Kullgren,¹¹ mental disorders manifest early and with considerable severity among parricide patients. Schizophrenia and delusional disorders are the most prevalent diagnoses among parricide offenders internationally, followed by adjustment disorder and personality disorders, particularly antisocial and borderline personality disorder.^4,12–16 Over half of patients with mental disorders who commit parricide are affected by schizophrenia.^2,17

Bojanić and colleagues¹⁷ supported Heide's typology of parricide offenders, with Class 1 corresponding to severely mentally ill offenders. Schizophrenia and delusional disorders predominated among offenders in this class. Mental illness was present in 67% of the overall sample of parricide perpetrators, with 40% classified as severely mentally ill and nearly 50% having prior contact with mental health services. Offenders with severe mental health problems, as identified in this classification, are often deemed unfit for trial and/or receive hospital disposal.^9,18 In contrast, Holt³ questioned the presumed prevalence of mental illness in parricide cases, noting that many incidents did not meet criteria for an irrational act or diminished legal responsibility, nor did they result in hospitalization orders. Ongoing debate in the literature surrounds the interpretation of Holt's conclusions.¹⁹

Aim

Despite increasing interest, the existing literature on parricide suffers from numerous methodological drawbacks.^17,20 Various authors have endeavored to characterize parricide offenders using diverse methodologies. The present study seeks to identify and elucidate differences between two groups of psychiatric patients who committed homicide and were found not guilty by reason of insanity (NGRI) by the court: those who committed or attempted homicide against their parents and a control group comprising offenders who targeted nonparent victims. To the best of the author's knowledge, no other study exclusively examines NGRIs and compares NGRI parricide offenders with NGRI homicide offenders. The authors underscore the critical importance of extensively studying this offender type to enable timely detection and intervention. A clear need for further knowledge of the subject is highlighted, even among authors who are highly active in this area of research.⁶ Furthermore, comprehensive, country-specific research studies on parricide incidents are essential for acquiring culturally relevant knowledge and understanding.

Methods

The sample of the present study included all patients hospitalized in the Department of Forensic Psychiatry in Thessaloniki, between January 2015 and January 2020 (N = 84). This department exclusively hospitalizes all patients deemed NGRIs in Northern Greece. According to Article 34 of the Greek Penal Code, such individuals are deemed NGRI when the court determines their incompetence and unaccountability. In these cases, court decisions prioritize the need for treatment, leading to hospitalization in state psychiatric facilities, specifically in Athens or Thessaloniki, depending on the individual's place of residence (as outlined in Articles 69 and 70 of the Greek Penal Code).²¹

Six patients were subsequently excluded from the study. Two individuals did not consent in participating and three more patients were excluded due to severe dementia, a condition not diagnosed before the offense. Finally, one patient was absent without leave at the time of the research. This study finally included all consenting patients who committed homicide or attempted homicide (N = 52).

Subjects were divided into two groups: the parricide group (N = 21) and the control group, consisting of individuals who committed or attempted homicide against others, primarily family members but not their parents (N = 31). Relevant data were collected using a structured case registry form, incorporating information from medical files and court expert opinions on offenders’ mental status. In-depth clinical insights were obtained through interviews with both inpatients and outpatients of the Department of Forensic Psychiatry, supplemented by input from department staff and patients’ relatives.

Patients were evaluated using several standardized scales: the Positive and Negative Symptoms Scale (PANSS), the Hostility and Direction of Hostility Questionnaire (HDHQ), the Aggression Questionnaire, the Historical, Clinical and Risk Management Scale-20 (HCR-20), and the Zuckerman-Kuhlman Personality Questionnaire. These tools provided comprehensive information on psychopathology, hostility, aggression, dangerousness, and personality traits. Court decisions also contributed to a comprehensive understanding of each case.

As most patients were already hospitalized for an extended duration, retrospective completion of the PANSS and HCR-20 scales was conducted to assess psychopathology and risk of violence at the time of the offense. Data from medical and court records describing symptoms at the time of arrest were incorporated into this retrospective evaluation, ensuring accuracy. To maximize the accuracy of this evaluation all additional information was used for this purpose. The item H7 (psychopathy) was not evaluated or included in the HCR-20 scale as the Psychopathy Checklist-revised (PCL-R) was not part of the tools used in this study.

Statistical analysis was performed using SPSS 23 (Statistical Package for Social Sciences 23), and all data and statistics are presented in the tables below, along with details of the conducted tests. Statistical significance was defined as p-values below .05.

Informed consent was obtained from all participants and their closest family members, if available. The study protocol was approved by the Bioethics Committee of the PHT and the Hellenic Data Protection Authority.

Results

The parricide group consisted of patients diagnosed with schizophrenia (N = 18) or other psychotic disorders (N = 3). The majority of victims in this group were mothers (N = 16), including one stepmother. The remaining victims were fathers (N = 5), including one stepfather. Twelve cases involved completed homicides, and nine were attempted homicides. In five cases, there were multiple victims.

The comparison group also comprised individuals diagnosed with schizophrenia (N = 23) or other psychotic disorders (N = 8). The victims in this group included grandmothers (N = 7), neighbors (N = 6), relatives (N = 5), female spouses (N = 4), offspring (N = 3), sisters (N = 2), strangers (N = 2), a mother-in-law (N = 1), and a friend (N = 1). Seventeen cases involved completed homicides, and 14 cases involved attempted homicides. In four cases, the offender attacked more than one individual.

The parricide group primarily consisted of men (90.5%) in their 30s (36.43 ± 10.26 years), and the majority were unmarried (71.5%). These individuals were diagnosed with schizophrenia, but the crime typically did not occur during their first psychotic episode. Most had prior contact with mental health services and had been hospitalized in the past (71.4%). Only a few (N = 3) were considered adherent to treatment at the time of the crime. Substance abuse (drugs, alcohol) was noted in about half of the cases before the crime (52.4%), but substance use at the time of the crime was observed in only a few cases (23.8%). A history of violence before the crime was prevalent (76.2%), although prior convictions were rare (14.3%). A third of the offenders reported a history of abuse (physical or sexual), and nearly 30% had a history of conduct disorder in childhood or adolescence. Stressful events before the crime, particularly bereavement, were noted in 38.1% of cases, and a significant number (23.8%) attempted suicide after the parricide. Sharp force was the predominant method used (81%), and the crimes were typically committed in private residences. The patients in the parricide group exhibited moderate to severe illness (PANSS score 113.29 ± 26.12) and had elevated hostility scores (HDHQ Total Hostility score 23.86 ± 8.75), indicating a heightened risk of violence both before and after the crime (HCR-20 total score of 26.33 ± 5.18 and 25.29 ± 6.51, respectively).

Statistical tests were conducted to compare the two groups of NGRIs studied, and the results are presented in the tables below. Each item of the PANSS and HCR-20 scales was evaluated both at the time of the crime and during the study period. For brevity, the detailed tables are not included in this paper but are available upon request. The parricidal group in our sample appeared to bear a higher risk compared to the control group of engaging in future violent behavior (higher total HCR-20 score). This finding could be attributed to both the elevated risk management scores and the observed clinical unresponsiveness to treatment (C5 item of the scale, 1.29 ± 0.85 vs 0.77 ± 0.76, p = .030). In contrast, scores on the other scales (HDHQ and Aggression Questionnaire) were found to be similar. Of note, the overall clinical impression is that the parricide group may be at a higher risk to manifest future violence, but this was not reflected in the scores of the other scales used for the purposes of the present study. It was demonstrated that parricidal offenders were perceived to be more dangerous compared to the control group in terms of risk management both prior to and following the index crime. In addition, although the two groups have comparable rates of hospitalization in general, the parricide group was noted to have a higher percentage of voluntary admissions than the control group (53.3% vs 21.1%), a finding which was marginally not statistically significant (p = .051). All results are listed in detail in the Tables 1 –5.

Discussion

The findings of this study align with existing literature, which indicates consistent characteristics among parricide offenders across different countries and time periods.^4,5,22 Biological parents are more frequently victimized compared to adoptive or foster parents.⁶ Adult parricide offenders are commonly diagnosed with mental illness,²³ particularly schizophrenia, although they often fail to adhere to prescribed medications at the time of the crime.^1,24–26 History of violence and substance abuse is prevalent among these offenders,¹ and many report being victims of abuse themselves.²⁷ Most parricides occur within shared residences,^17,24 often involving sharp force in regions where firearms are less accessible.^6,28

In Greece, the low rate of prior convictions despite a history of violence may be attributed to underreporting of intrafamily assaults due to societal and familial dynamics, where assaults within the family or even in the neighborhood remain frequently unreported.^21,29 Victims in Greece frequently exhibit high tolerance to domestic violence, and incidents are often concealed due to a sense of shame. Consequently, only serious crimes may be prosecuted when the offender is identified as mentally ill, despite the high incidence of previous attacks on the victim that is often observed.^17,30 It has also been commented that relatives of people suffering from serious mental disorders may be tolerant to violence, considering it unavoidable.³¹

Family members, particularly mothers, are often primary caregivers for mentally ill individuals and may be targeted by offenders due to perceived grievances related to treatment adherence. They are also burdened with the duty of notifying the prosecutor and/or the police in case of the need for involuntary hospitalization. Parents can, therefore, often be targeted by the mentally ill offspring and persistently maltreated and abused.^25,32,33 It has also been established, both within relevant literature as well as in the present study, that, in most cases, noncompliance to treatment is encountered, thus underlining a critical factor involved.^25,27

NGRI parricide offenders of this study were found to differ significantly from NGRI offenders of homicide or attempted homicide in the variables discussed. This finding could lead to the assumption that mentally disordered offenders of homicide within the extended family have similar features, both clinical, forensic, and demographical, independently from the actual relationship with the victim (parent, spouse, sibling, grandparent, etc.). The absence of many statistically significant differences between the two groups in our study could be attributed to the close offender–victim relationship that was present in most cases. Spouses, siblings, and grandparents can also play a significant role in the life of a seriously mentally ill individual in Greece. Members of the extended family often fill the gaps in the provision of clinical care for the mentally ill. Therefore, offence-provoking events like threatening of involuntary hospitalization and forcing medication on the patient before the homicide could be found in both groups of our study.²⁵ Further research on the underlying dynamics of these close relationships is needed. Factors including family structures and dynamics, patterns of caring, as well as welfare and access to healthcare services should all be considered when analyzing this phenomenon.¹⁹

Despite comparable rates of hospitalization, the parricide group exhibited marginally more voluntary admissions, possibly indicating a proactive attempt to manage familial conflicts or avoid stressful environments, based on information obtained in the interviews conducted as a part of this research. The parricide group also demonstrated a higher risk of future violent behavior, possibly among those clinically unresponsive to treatment, contrary to research results indicating that homicides committed in the domestic context do not tend to recur.²⁴ However, scores on the other scales (HDHQ and Aggression Questionnaire) were found to be similar. Further research is necessary to shed light on the violence or criminality exhibited by mentally disordered parricidal offenders in the long-term.

Limitations

One potential limitation of our study is the exclusive enrollment of patients sentenced to psychiatric treatment within the Department of Forensic Psychiatry in Thessaloniki, which restricted the size and diversity of our sample. Consequently, our sample could be regarded as highly specific, impacting both the total number of participants and the representativeness of our findings, thus potentially limiting the generalizability of our results.

A notable strength of our study, however, lies in the inclusion of a substantial number of participants from across the nation. This encompassed all consenting homicidal offenders hospitalized in Northern Greece between January 2015 and January 2020, ensuring a comprehensive representation of cases within this geographic area.

Conclusions

Clinical studies focusing on parricide offenders are widely recognized as crucial for enhancing our understanding of this complex phenomenon. However, their utility is often constrained by relatively small sample sizes.⁶ Moreover, the importance of locally sensitive data cannot be overstated, considering the significant influence of cultural, national, and regional variations on the dynamics of parricide.¹⁹

In the current study, we reaffirmed and expanded upon the characteristic features described in existing literature concerning parricide offenders. Our investigation provided valuable insights into aggression, hostility, psychopathology, and risk assessment among offenders found NGRI for parricide, shedding light on the clinical profile of NGRI parricide offenders. This study also underscores the cultural and societal factors that influence the dynamics of parricide cases, illuminating the challenges in identifying and addressing domestic violence and mental health issues within Greek communities.

Comparison between parricide and homicide NGRI offenders revealed striking similarities, with notable differences primarily observed in specific variables discussed above. This divergence could potentially be explained by the unique dynamics inherent to intrafamilial relationships, necessitating further exploration. However, caution is warranted in drawing definitive conclusions due to the need for larger sample sizes to ensure the validity and generalizability of findings. Future research endeavors should focus on confirming and expanding upon these hypotheses.

In conclusion, parricide remains a rare yet serious event with distinct clinical and sociodemographic features. Mental health professionals should be vigilant in assessing familial violence risks and providing timely interventions to prevent such tragedies.³⁴ Early intervention, evaluating the presence of risk factors,³⁵ supporting families with social interventions, helping patients deal with their conflicts, and reintegrating them into society could save lives.³⁶

Table 1.

Results of the independence tests regarding the demographic characteristics and the clinical characteristics of the participants.

	Parricide(Ν=21)		Homicide (Ν=31)
Variables	Ν	%	Ν	%	x ²	p*
Gender (N = 52)**
Male	19	90.5	26	83.9	0.469	.687
Female	2	9.5	5	16.1	0.469	.687
Time of crime perpetration (N = 52)
At the first psychotic episode	6	28.6	12	38.7	0.569	.451
In the course of the illness	15	71.4	19	61.3	0.569	.451
Marital status (Ν = 52)***
Married	2	9.5	11	35.5	5.063	.310
Unwed/single	14	66.7	15	48.4
Unwed in relationship	1	4.8	1	3.2
Divorced	2	9.5	3	9.7
Widowed	2	9.5	1	3.2
Hospitalizations until index crime (N = 52)	15	71.4	19	61.3	0.569	.451
Involuntary hospitalizations until index crime (N = 52)**	10	66.7	18	94.7	4.545	.066
Voluntary hospitalizations until index crime (N = 52)	8	53.3	4	21.1	3.825	.051

*In cases where p < .05, the relationship with the victim is significantly associated with this variable.

In these cases, Fisher's exact test was performed.

***In these cases, the Monte Carlo method was applied.

Table 2.

Results of independence tests regarding the use of psychotropic/addictive substances and receiving treatment at the time of the perpetration of the offense.

	Parricide(Ν = 21)		Homicide(Ν = 31)
Variables	Ν	%	Ν	%	x ²	p*
Substances (Ν=52)	11	52.4	16	51.6	0.003	.957
Substance abuse around the perpetration of the crime (N = 52)	5	23.8	10	32.3	0.435	.509
Committing a criminal act related to psychotropic substances (N = 52)**	3	14.3	8	25.8	0.996	.491
On psychiatric medication at time of the offense (N = 52)	18	85.7	22	71	1.534	.318
Compliance with psychiatric medication at the time of the offense (N = 40)**	3	16.7	1	4.5	1.616	.310

*In cases where p < .05, the relationship with the victim is significantly associated with this variable.

In these cases, Fisher's exact test was performed. The remaining independence tests were performed with the Pearson's chi-square test for independence.

Table 3.

Results of independence tests regarding history of self-destructiveness or violence against others, victimization, stressful life events, and organic pathologies.

	Parricide(Ν = 21)		Homicide(Ν = 31)
Variables	Ν	%	Ν	%	x ²	p*
Attempted suicide until the perpetration of the crime (N = 52)	6	28.6	10	32.3	0.080	.777
Attempted suicide after the perpetration of the crime (N = 52)	5	23.8	9	29	0.174	.677
Violent behavior until the perpetration of the crime (N = 52)	16	76.2	23	74.2	0.027	.870
Violent behavior behavior after the perpetration of the crime (N = 52)**	2	9.5	7	22.6	1.491	.283
History of victimization in the patient's past (N = 52)	7	33.3	12	38.7	0.156	.693
Victim of physical/sexual abuse (N = 52)	6	28.6	12	38.7	0.569	.451
Victim of school bullying (N = 52)**	3	14.3	2	6.5	0.884	.383
History of prior convictions (N = 52)**	3	14.3	4	12.9	0.021	1.000
History of conduct disorder (N = 52)	6	28.6	10	32.3	0.080	0.777
Stressful life events in the last 24 months before the crime (N = 52)	8	38.1	19	61.3	2.698	0.100
Organic pathologies until/at the time of the crime perpetration (N = 52)**	0	0	3	9.7	2.157	0.264

*In cases where p < .05, the relationship with the victim is significantly associated with this variable.

**In these cases, Fisher's exact test was performed. The remaining independence tests were performed with the Pearson's chi-square test for independence.

Table 4.

Results of independence tests regarding the means and the place of the crime.

	Parricide(Ν = 21)		Homicide(Ν = 31)
Variables	Ν	%	Ν	%	x ²	p
Weapon/means of the crime (N = 52)
Blunt object	1	4.8	1	3.2	8.481	.195
Sharp instrument	17	81	14	45.2
Noose	1	4.8	2	6.5
Vehicle	0	0	1	3.2
Fire	0	0	4	12.9
Body (fists, legs, etc.)	1	4.8	4	12.9
Firearm	1	4.8	5	16.1
Place of the crime (N = 52)
Public place	0	0	4	12.9	2.935	.138
Private residence	21	100	27	87.1	2.935	.138

In every case the Monte Carlo method was used.

Table 5.

Results of difference tests in the overall scores of the participants.

		Parricide(Ν = 21)	Homicide(Ν = 31)
Questionnaires	Subscales	Mean value ± SD	Mean value ± SD	t/U	p*
Demographics	Age of crime enactment	36.43 ± 10.26	37.58 ± 14.28	324.000	.978
The Aggression Questionnaire	Physical Aggression(5–45)	20.48 ± 8.48	18.06 ± 9.48	264.000	.250
	Verbal Aggression(5–25)**	12.67 ± 4.08	12.71 ± 2.96	−0.044	.965
	Anger (7–35)**	15.38 ± 5.62	12.84 ± 4.51	1.805	.077
	Hostility (8–40)**	22.48 ± 7.42	21.87 ± 7.76	0.281	.780
The Hostility and Direction of Hostility Questionnaire	Urge to Act Out Hostility (0–12)	4.19 ± 3.01	4.39 ± 2.70	296.000	.577
	Criticism of Others (0–12)**	6.86 ± 2.82	5.90 ± 2.90	1.177	.245
	Projected Delusional or Paranoid Hostility (0–9)**	4.33 ± 2.37	4.65 ± 2.84	−0.415	.680
	Self-Criticism(0–11)**	4.52 ± 2.66	4.39 ± 2.22	0.201	.841
	Delusional Guilt (0–7)	3.95 ± 1.96	3.48 ± 1.48	0.981	.331
	Total Hostility(0–51)**	23.86 ± 8.75	22.77 ± 9.15	0.426	.672
	Extrapunitiveness (0–33)	15.38 ± 7.03	14.90 ± 7.31	314.000	.830
	Intropunitiveness(0–29)**	13.52 ± 7.18	12.45 ± 6.15	0.576	.567
	Direction of Hostility	−2.38 ± 9.17	−2.65 ± 6.97	297.500	.601
Zuckerman- Kuhlman Personality Questionnaire	Impulsive Sensation Seeking (0–100)	38.35 ± 27.00	40.07 ± 23.29	295.000	.568
	Impulsivity (0–100)**	36.31 ± 28.20	41.94 ± 28.97	−0.694	.491
	Sensation Seeking(0–100)	39.82 ± 29.11	38.71 ± 28.17	324.500	.985
	Neuroticism Anxiety (0–100)**	44.36 ± 25.98	38.03 ± 20.86	0.972	.336
	Aggression-Hostility (0–100)	39.21 ± 17.87	34.35 ± 23.58	246.500	.138
	Activity (0–100)	51.26 ± 21.38	43.64 ± 24.24	278.000	.373
	Sociability (0–100)	40.90 ± 20.08	43.83 ± 22.26	291.000	.516
Positive and Negative Syndrome Scale	Positive scale at the time of the offense (7–49)**	32.24 ± 6.57	32.03 ± 5.71	0.120	.905
	Negative scale at the time of the offense (7–49)**	25.95 ± 8.80	23.39 ± 6.66	1.196	.237
	General Psychopathology scale at the time of the offense (16–112)**	55.10 ± 13.18	54.77 ± 10.22	0.099	.922
	Total score at the time of the offense(30–210)**	113.29 ± 26.12	110.19 ± 17.88	0.473	.640
	Positive scale at present (7–49)**	18.67 ± 8.38	17.55 ± 7.49	0.504	.617
	Negative scale at present (7–49)**	25.14 ± 9.09	24.42 ± 8.73	0.288	.774
	General Psychopathology scale at present(16–112)**	42.14 ± 10.14	39.45 ± 10.65	0.912	.366
	Total score at present (30–210)**	86.19 ± 24.41	82.35 ± 23.48	0.569	.572
Historical, Clinical and Risk Management—20 (HCR—20)	Historical scale at the time of the offense(0–18)	11.57 ± 2.32	10.52 ± 2.79	251.500	.164
	Clinical scale at the time of the offense (0–10)	7.43 ± 2.01	7.52 ± 1.48	310.500	.775
	Risk Management scale at the offense (0–10)**	7.33 ± 2.35	5.45 ± 2.51	2.717	.009
	Total score at the time of the offense (0–38)**	26.33 ± 5.18	23.48 ± 5.30	1.920	.061
	Historical scale at present (0–18)**	13.05 ± 1.91	12.03 ± 2.69	1.492	.142
	Clinical scale at present (0–10)**	4.90 ± 3.19	4.23 ± 2.66	0.834	.408
	Risk Management scale at present (0–10)	7.33 ± 2.35	5.45 ± 2.51	190.500	.011
	Total score at present (0–38)**	25.29 ± 6.51	21.71 ± 6.08	2,022	.049

*In cases where p < .05, the history of conduct disorder is significantly associated with this variable.

**In these cases t-test was applied for two independent samples (Independent Samples t-test). The nonparametric Mann–Whitney U test was applied to all other scores.

Footnotes

Acknowledgments

The authors express sincere gratitude to Dr Vasiliki Garmiri for her valuable editorial assistance in refining this research paper. Her insightful feedback and contributions were greatly appreciated and have enhanced the clarity and quality of the manuscript.

Declaration of conflicting interests

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

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Maria Markopoulou

Pavlos Pavlidis

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