The Link Between Adverse Childhood Experiences and Mental Health in Offenders: A Systematic Review

Introduction

Adverse childhood experiences (ACEs) are potentially traumatic events that occur during childhood and can be stressful to an individual’s health, which include neglect, physical, emotional, and sexual abuse, living in a dysfunctional household, substance dependence, and having a family member in prison. An unstable family environment, the death of a parent, substance abuse by a close relative, mental illness, or parental separation during childhood, among other potentially traumatic situations, have also been considered risk factors for future criminal behavior (Marques, 2020) as offenders are more likely to have higher rates of adverse childhood experiences than the general population (Basto-Pereira et al., 2016). There is a high prevalence of different types of victimization in offenders (Wemmers et al., 2017; Wojciechowski, 2020), and inmates tend to show more experiences of ACEs than the general population (Almeida & Costa, 2023). Although it is not enhanced how ACEs occurring in childhood influence an individual to commit a crime, these ACEs can have an impact on criminal behavior and mental health (Marques, 2020; Matos, 2019). A recent systematic review showed that having a specific activity routine in unsafe neighborhoods by putting participants close to motivated offenders increases the risk and frequency of victimization and consequently promotes the adaptation of deviant behaviors (Pires & Almeida, 2023).

Mental welfare encompasses how people feel and cope with their daily lives, and there is an increased risk of mental health issues and self-harming behaviors in incarcerated individuals (Marques, 2020). Prison populations have a high prevalence of mental illness (Sirdifield, 2012), and a considerable percentage experience comorbidity of mental health issues and adverse childhood experiences. Studies have shown that those with mental illness have higher re-arrest rates and are more likely to replicate violent behaviors (Skeem et al., 2014). Prisoners often present multiple and complex health needs, and their mental health and well-being can have a negative effect due to experiencing isolation and lack of privacy (Konrad et al., 2007).

There has been an increased rate of self-harm in the male adult prison population in England and Wales, where there were reported over 43,000 incidents in 2018, with a total of 54% within 1,000 incarcerated individuals (Ministry of Justice, 2019). In American jails, suicide is the leading cause of death, which is approximately three times higher rate in jails when compared to the general population (Calli & Jared, 2024). In the European panorama, Portugal is one of the countries with the highest suicide rate. According to the report for 2022 (Aebi et al., 2022), the suicide rates in Portuguese prisons are high, with scores between 5.1% and 25% higher than the European median value.

Researchers suggest that ACEs are also risk factors for poor mental health in adulthood (Marzano et al., 2011). The adverse outcomes of these experiences increase the outcomes according to the number of ACEs types experienced. Therefore, a secure relationship between mental health and ACEs can be identified, along with deviant behaviors leading to criminal justice involvement (Hughes et al., 2017). Additionally, homelessness, low education, being on remand, and serving a life sentence are risk factors for self-harm and suicidal behaviors that influence these rates (Pope, 2018).

James and Glaze (2006) reported that, in 2006, more than half of male and female prisoners expressed mental health issues, and almost 25% of this population had revealed a history of physical or sexual abuse. Within these mental health problems, it is typical to endorse five or more symptoms of major depressive disorder, symptoms of mania, and reporting delusions and hallucinations. The mental illnesses are often unrecognized and untreated (Brooker & Glyn, 2012). Ford et al. (2020) stated that offenders reporting multiple ACEs were more prone to have poor mental health. A survey of incarcerated men revealed that almost half of the sample disclosed a chronic mental illness, and nearly a third revealed lifetime suicide attempts and self-harm. Increased risks of chronic mental illness and suicide attempts were identified in participants who had experienced four or more ACEs during childhood. In contrast, risks were even higher for those who experienced two or more ACEs during childhood. In essence, prisoners who experienced four ACEs or more were 15 times more prone to have lifetime self-harm and 8 times more prone to attempt suicide in prison settings. Inmates who experienced multiple ACEs are more prone to engage in self-harm behavior and mental illness under confinement (Ford et al., 2020).

Offenders also face diverse adversities in mental health services while in an incarcerated environment, where there is a lack of appropriate conditions for those with complex health needs (Bradley, 2009). According to James and Glaze (2006), a small number of prisoners with mental health issues receive mental health treatment at the jail and take prescribed medication. Due to this disproportionately high prevalence of mental disorders among this population, there should be easy access to health care in the criminal justice system (Fazel & Seewald, 2012).

There is a higher frequency of psychiatric issues in older prisoners, compared to the younger ones, with comorbid mental illnesses, including psychoses, dementia, depression, and a psychiatric disorder. This includes psychotic and mood disorders, substance use, personality, and neurodevelopmental disorders. It is suggested that these results may be a consequence of the prison environment and the traumatic and stressful experiences (Haesen et al., 2019). In their study, Ignatyev et al. (2019) identified that more than half of inmates had one mental health problem. Among those, a high percentage has shown three or more mental disorders, with antisocial and borderline personality disorders and anxiety disorders. A cross-sectional review of the Mental Health in the Prison Population has shown the pervasiveness of mental disorders within incarcerated individuals. Offenders reported a high rate of major depressive disorder, anxiety disorders, and a risk of suicide. Comorbidities are also frequent; nearly half of the sample presented two or more substance abuse or psychiatric disorders. This sample was compared to a general population sample, demonstrating a significantly higher prevalence of mental health disorders in an offender population (Fovet et al., 2020). Other studies indicate that inmates, compared to the general population, have higher values of substance abuse (Pflugradt et al., 2017), mental illness (Tyler et al., 2019), and higher levels of emotional lability (Almeida et al., 2024).

Although there are studies that present outcomes of ACEs in the inmate population or the general population, comparative studies between these populations are scarce. Studies about mental health highlighted that there is often a high range of offenders who experience mental illnesses and are not given the proper healthcare access treatment while on probation (Fazel & Seewald, 2012). Mental health care for individuals incarcerated is a challenge. One primary factor is the limited resources within prisons, leading to a shortage of mental health professionals, insufficient funding for programs, and inadequate staff training (Weil, 2015). Compounding this problem, the pervasive stigma surrounding mental health issues arises, both within society and specifically within correctional settings. This stigma can result in a lack of awareness and understanding of the prevalence and severity of mental health conditions among inmates, further contributing to the insufficient attention and care they receive (Lamb & Weinberger, 2001). The high rates of incarceration of individuals with pre-existing mental health conditions exacerbate the demand for mental health services within prisons. Screening and assessment processes during intake may also be insufficient, leading to undiagnosed or untreated mental health issues. A lack of continuity in mental health care is often experienced by inmates transitioning between prisons or upon release (Priebe et al., 2008). Furthermore, the punitive nature of correctional systems historically places a greater emphasis on punishment than rehabilitation, potentially neglecting the mental health needs of those in custody and perpetuating a cycle of reoffending (Lamb & Weinberger, 2001).

Thus, this systematic review aimed to analyze and synthesize the literature, exploring the relationship between ACEs and mental health in adult offenders. The objective is to conduct a comprehensive synthesis of existing research, seeking not only to identify patterns and correlations but also to extract actionable insights that can significantly impact the development of targeted intervention strategies. Through a meticulous analysis of selected articles, our synthesis endeavors to provide a robust foundation of knowledge. This foundation is poised to inform various facets of the field, including shaping the trajectory of future research endeavors, guiding the formulation of evidence-based policies, and influencing the design of practical interventions. By explicitly addressing the intricacies of ACEs and mental health among adult inmates, our systematic review seeks to advance scholarly discourse and empower practitioners, policymakers, and researchers with valuable insights that can drive positive change in criminology and mental health. By addressing this gap in the literature, it aspires to provide valuable knowledge that can guide future research, policy development, and practical interventions in the field.

Method

Data Management and Selection

The selection process of the articles comprised in this study is shown in Figure 1. Articles were reviewed in the following order: title, abstract, and full text. Three hundred seventy articles were identified through the database search. After removing duplicated articles, 220 were established. Posteriorly, titles and abstracts were screened, which led to a total of 19 articles. The inclusion criteria previously stated were implemented in these articles, resulting in the final 12 articles. Data extraction contained: (1) adolescent population samples; (2) non-offending samples; (3) not measuring adverse childhood experiences and mental health; (4) not being written in English; and (5) not being a scientific article.

OPEN IN VIEWER

Figure 1.

Flow diagram of the studies selection.

The authors independently extracted data from articles that meet the inclusion criteria. Discrepancies were discussed until a mutual agreement. The reliability of the agreement between the authors was assessed based on the standard criteria of Cohen’s kappa statistic. Interpretation of the kappa statistic (κ) for the inter-rater agreement was: <.20 (slight), .21 to .40 (fair), .41 to .60 (moderate), .61 to .80 (good), and >.81 (excellent; McHugh, 2012). The reliability of the agreement between the authors is excellent (.83).

Results

Study Sample

The studies comprised a total of 29,244 inmates. The characteristics of each sample, the country, and the key findings are described in Table 1. The samples differed in sex, age, and size. Participants were adults with ages greater or equal to 18 years old. Of the total studies, two comprised samples of female and male participants, three focused on female inmates, and seven focused on male inmates. The smallest sample size matched the number of 75 participants (Pflugradt et al., 2017), and the study with the largest sample size matched the number of 24,848 participants (Henry, 2022). Additionally, one of the studies focused on a sample with both sexual offense and intentional homicide perpetrators (Pflugradt et al., 2017), while the others integrated offenders with diverse types of aggression. Of the 12 studies, 6 were performed in the United States of America (e.g., Henry, 2022; Lawrence, 2022; Messina, 2022), 1 was conducted in France (Arnal et al., 2018), 1 in Spain (Caravaca-Sánchez et al., 2019), 1 in Mexico (Pérez-Ramírez et al., 2021), 1 in Canada (Hilton et al., 2019), 1 in Germany (Ullrich & Marneros, 2007), and 1 in Wales (Ford et al., 2020).

OPEN IN VIEWER

Table 1.

Characteristics of Reviewed Studies.

Authors	Country	Sample characteristics	Key findings
Arnal et al. (2018)	France	798 incarcerated men; the mean age was 36 years old.	The inmates from Martinique had significantly more ACEs and were charged with longer sentences in prison compared to the mainland France group. The Martinique sample had significantly fewer major depressive disorders. Psychiatric profile differences were identified between the two groups, where the prevalence of psychosis is four times lower compared to the mainland France group. Lower rates of mental health issues were found in Martinique’s jail. Offenders, who keep in touch with their relatives and sustain family support, have better mental health and a lower prevalence of mental disorders.
Cavaca-Sánchez et al. (2019)	Spain	174 incarcerated women; the mean age was 38	Incarcerated participants reported exposure to victimization during childhood, whereas one-third of women reported emotional abuse, followed by physical and sexual abuse. Incarcerated women who reported ACEs stated low levels of social support and higher levels of mental illness.
Ford et al. (2020)	Wales	468 Incarcerated men; aged from 18 to 69 years old.	Most participants had at least one ACEs, and 45.5% suffered ≥4 ACEs. The likelihood of experiencing lifetime mental illness, engaging in self-harm or suicide attempts, and having low mental well-being rises with greater exposure to ACEs. Participants who reported ≥4 ACEs described four times more suicide attempts, lifetime mental illness diagnosis, self-harm, and low mental well-being. Male prisoners who have suffered multiple ACEs were more prone to have self-harm or suicide attempts, low mental welfare, and lifetime mental disorders.
Henry (2022)	USA	24,848 incarcerated males and females; 25% women and 75% men; the mean age was 39 years old.	Individuals with multiple mental disorders may receive more harsh disciplinary action, as in solitary confinement in jail. The urge to violate the rules within the prison and the identification of people who embrace that behavior can be related to ACEs. Participants with ACEs history were being retraumatized in prison, exacerbating their behavioral problems in these settings and when integrated into society.
Hilton et al. (2019)	Canada	435 incarcerated men; the mean age was 34 years old.	Individuals who committed intimate partner violence displayed the highest average ACE score, demonstrated a greater inclination towards violent and non-violent criminal behaviors in their history, and exhibited characteristics of psychopathy. Non-violent offenders had lower scores on ACEs. In the overall group of offenders, ACEs substantially impacted all models of criminal inclination except for institutional assaults.
Lawrence (2022)	USA	398 incarcerated women (does not refer the participants’ age).	Female inmates who displayed frequent sociability, responsibility, and diligence were more inclined to maintain positive attitudes regarding their self-efficacy. Conversely, those who reported high levels of neuroticism were less likely to tackle daily challenges and had lower confidence in their capabilities. Female offenders who exhibited symptoms of mental health issues tended to hold negative attitudes concerning self-efficacy. In contrast to conscientiousness and extraversion, attitudes toward self-efficacy were negatively associated with ACEs, mental illness, and neuroticism.
Messina (2022)	USA	624 incarcerated men; the mean age was 40 years old.	Incarcerated participants reported extensive histories of ACEs, experiencing sexual abuse (29%), physical neglect (33%), emotional neglect (50%), physical abuse (64%), and verbal abuse (67%). A significant proportion of participants reported elevated occurrences of adverse family situations, including parental separation (71%), household alcohol or drug abuse (61%), domestic violence at home (38%), substance use within the household (64%), family history of mental illness (32%), and a 44% rate of family member incarceration. Participants experienced notable improvements in their trauma-related mental health symptoms because of the exploring trauma intervention, which significantly reduced depression, anxiety, and PTSD symptoms.
Messina and Schepps (2021)	USA	682 incarcerated women and 624 men; the mean age of women was 37 years old, and the mean age of men was 40.	The health trauma and exploring trauma interventions found positive changes among participants, reinforcing that trauma-specific programs should be more broadly implemented in prisons.
Pérez-Ramírez et al. (2021)	Mexico	184 male offenders; the mean age was 40 years old.	Global severity index (GSI) and ACEs significantly influenced suicidal ideation (SI). Age, GSI, and ACEs were significant predictors of suicidal behavior (SB). Higher GSI was positively associated with SI and SB. Those with higher ACEs scores were also more likely to endorse SI and SB. Individuals with a history of mental illness face an elevated risk of experiencing thoughts of SI and SB. SI and SB were significantly associated with age, anxiety, depression, anger, and GSI and ACEs.
Pflugradt et al. (2017)	USA	75 incarcerated females; perpetrators of intentional homicide (n = 28) and perpetrators of sexual offenses (n = 47); the mean age was 42 years old.	A significant majority of participants convicted of homicide (82%) disclosed that they had experienced four or more ACEs, while 71% reported encountering five or more such experiences. Homicide offenders were the ones who reported significantly more ACEs compared to the sexual offenders. The female homicide perpetrators reported a significantly greater number of dysfunctional domain items, substance abuse, mental illness in the home, and ACEs, except for sexual abuse. About 100% of homicide offenders reported at least one ACEs. About 82% of the male homicide offenders reported four or more ACEs, compared to 15% of the general female population. Sexual offenders and homicide perpetrators similarly shared experiencing sexual abuse, domestic violence in the household, divorced parents, and having an incarcerated family member during childhood.
Skarupski et al. (2015)	USA	192 incarcerated men; the mean age was 41 years old.	Of the death and trauma events, 16% reported the death of a parent, 24% the death of a sibling, 32% the murder of a family member, and 46% an incarcerated family member. About 50% reported witnessing and getting physical abuse more than once during childhood. Regarding physical abuse, 17% reported being at least 5 years old when touched sexually, and 14% of the sample indicated that someone at least 5 years older had attempted to engage them in unwanted sexual contact. Less than 10% of the participants in the study reported having no ACEs, where one ACEs was indicated by 11%, two ACEs by 14%, and three ACEs. By 16% and four or more ACEs by half of the participants. About 90% of the sample reported at least one ACEs. Men who encountered trauma, abuse, and loss during childhood exhibited higher depressive symptoms and reduced quality of life than men who did not share similar ACEs.
Ullrich and Marneros (2007)	Germany	366 incarcerated men; the mean age was 32 years old.	The highest correlation was found between dissocial personality disorder (PD) and the impulsive type of emotionally unstable PD. Sexual abuse and a disrupted family background before a certain age were identified as risk factors for developing the psychopathic PD dimension. Moreover, frequent career changes and being raised with a sole, predominant career path were notably linked to psychopathic PD. Individuals with neurotic personalities seem at risk for developing comorbid mental disorders characterized by emotional distress, and their cognitive limitations appear to play a role in developing detached personality traits.

Discussion

The present systematic review aimed to analyze and synthesize the literature, exploring the relationship between adverse childhood experiences and mental health in adult offenders. The analysis of 12 scientific articles included in this study showed findings consistently and followed one another, where ACEs affect the offenders’ mental health and criminal behavior.

Results demonstrate that physical abuse, emotional abuse, the death or incarceration of a parent, and physical or sexual abuse are the most frequent ACEs identified by criminal offenders, and ACEs are expected within the offender population (Henry, 2022). Compared to general populations, more ACE experiences and a higher total number of maltreatments are evidenced in individuals who have committed a crime (Skarupski et al., 2015). Studies have revealed that the presence of ACEs differs according to gender and the type of offense (Pflugradt et al., 2017). Neglect, verbal and physical abuse, and a family member in incarceration were significantly more likely to be reported by men. In contrast, women often reported more sexual abuse and mental illness in the household (Henry, 2022).

On the other hand, similar rates of domestic violence, parental separation or divorce, emotional abuse, and substance use in the home were exposed by both genders. Furthermore, concerning gender, the female perpetrators who committed homicide population endorsed higher ACE scores among all items (Pflugradt et al., 2017). Nevertheless, regardless of gender, this population shows a marked presence of ACEs and mental health issues (Ford et al., 2020; Pérez-Ramírez et al., 2021), considered risk factors for future criminal behavior in an individual.

According to Pflugradt et al. (2017), homicide offenders, regardless of gender, have experienced a significantly higher ACEs than other criminal offenders. The most commonly reported ACEs among participants in various studies include physical abuse, emotional abuse, sexual abuse, and the death or incarceration of a parent (Ford et al., 2020; Henry, 2022). These ACEs can profoundly affect a child’s mental health, personal skills, and relationships, potentially influencing dysfunctional or criminal behavior in adulthood. Individuals with higher ACEs also exhibited higher negative emotional states (Ford et al., 2020). Mental health issues were prevalent among all samples of offenders and did not differ significantly based on the type of offense committed. Furthermore, higher ACE scores were associated with increased negative emotional states (Pflugradt et al., 2017; Skarupski et al., 2015).

The study conducted by Pflugradt et al. (2017) found that 25% of the population of sexual offenders did not report any ACEs. However, for those sexual offenders who did experience childhood abuse, it was suggested that their abusive experiences directly affected their engagement in sexual offenses. These individuals may perceive their childhood victimization as normal sexual conduct, leading to distorted views of sex and inappropriate behaviors toward others, as Steely (2023) supports.

On the other hand, a recent study by Almeida and Costa (2023) found no significant differences in childhood sexual victimization scores or benevolent childhood experiences between sex offenders and the general population. This suggests conflicting findings in the literature regarding whether experiencing childhood sexual abuse leads to sexual assault behavior in adulthood.

The relationship between ACEs and mental health problems in offenders has been well-established in the literature, as demonstrated by studies such as Almeida et al. (2024). Individuals who have experienced four or more ACEs are at increased risk for lifetime mental illness diagnosis and suicide attempts. They are 15 times more likely to engage in self-harming behavior and 8 times more likely to attempt suicide in prison (Ford et al., 2020). Even individuals who have experienced two or more ACEs are more likely to engage in these harmful behaviors (Ford et al., 2020). This highlights that offenders who have experienced ACEs throughout their lifetime are more vulnerable to experiencing poor mental health and engaging in self-harm.

Nevertheless, the relationship between ACEs and mental health is intricate and influenced by various factors. Several moderating and mediating variables intervene in ACEs’ impact on mental health throughout individuals’ development and adulthood (Crandall et al., 2019). Benevolent childhood experiences have been identified as moderators in the ACEs and mental health relationship. These positive experiences, such as supportive relationships and stable environments, can mitigate the adverse effects of ACEs (Almeida et al., 2023). Resilience, the ability to bounce back from adversity, can also be a significant moderator. Individuals with higher levels of resilience possess better-coping mechanisms and may be more adept at handling the impact of ACEs on mental health. Resilience is often characterized by strong coping skills, a positive self-image, and a robust social support network (Almeida et al., 2021).

Emotional intelligence emerges as a critical factor in the relationship between ACEs and mental health. The capacity to understand and manage emotions can act as a mediator, potentially lessening the adverse impact of ACEs on mental health (Morales, 2022). Emotional intelligence enhances coping strategies and fosters healthier interpersonal relationships. A sense of purpose or meaning in life is also essential (Subhi et al., 2012). Individuals who find meaning in their experiences are more likely to show psychological resilience, helping them overcome the adverse effects of ACEs on mental health (Tranter et al., 2021). Additionally, social support from friends, peers, and community networks can alleviate psychological distress associated with ACEs, promoting overall mental well-being (Morales, 2022).

It is important to note that mental illness can negatively impact individuals’ emotions and behavior, potentially leading to criminal conduct (Ford et al., 2020). This emphasizes the interplay between ACEs, mental health, and criminal behavior. Understanding and addressing these complex relationships is crucial for providing adequate support and interventions to offenders who have experienced ACEs and are at risk of experiencing mental health issues and engaging in self-harm behavior.

Conclusion

The current research proposes valuable future implications. Firstly, it emphasizes the need to adjust prison conditions for offenders to help them adopt non-deviant behavior inside and outside when released into society, reducing recidivism rates. To do so, some strategies are suggested. Research has shown that exploring trauma through mental health treatment programs helped incarcerated men and women with an ACEs complex history who were responsive to trauma-specific treatment (Messina, 2022; Messina & Schepps, 2021). As such, this approach could be implemented in these establishments to reduce criminality. Sending inmates to solitary confinement has been criticized for accentuating their bad conduct behavior and retraumatizing them (Henry, 2022). The current aim of prisons is to reeducate and to help these people not replicate deviant behaviors and follow the social norms when living in society instead of solely punishing them and not showing how they can follow a different path once out of jail. Further research should consider the time an individual’s mental health issues or mental illness, as well as ACEs, has unfolded in their lifetime to establish a more in-depth relationship between these two variables.