Child maltreatment is a representative traumatic childhood experience, including physical, emotional, and sexual abuse, and neglect [1,2]. Unfortunately, it is a common public health issue [3]. It is globally estimated that up to 1 billion children aged 2-17 years have experienced any form of physical, sexual, or emotional violence or neglect in the past [4]. In South Korea, the number of suspected case reports has continuously risen, mounting up to 52,083 cases, of which 72.2% (37,605 cases) were finally judged as child maltreatment crime cases in the year 2021 [5].

Notably, child maltreatment negatively impacts the affected children’s physical and psychological well-being [3]. While physical consequences of abuse (e.g., injury, death) can be visible and apparent, psychological consequences may be invisible or overlooked if not carefully assessed. However, there is ample evidence that exposure to childhood maltreatment is a robust risk factor for various short- and long-term mental health problems, raising the need for early detection of psychological after-effects. For example, in a systematic review and meta-analysis, child maltreatment was associated with a higher likelihood of being diagnosed with depressive disorder, anxiety disorder, or post-traumatic stress disorder (PTSD) [1]. Similarly, the experience of child maltreatment demonstrated a medium-sized effect for both internalizing (e.g., depression, anxiety) and externalizing (e.g., aggression, impulsivity) problems of children in a meta-analysis of research focusing on the relation between child maltreatment and psychosocial maladaptation from 1990 to 2016 in South Korea [6]. Child maltreatment was not only associated with the development of major psychiatric symptoms and disorders in childhood and adulthood, but it was also related to earlier onset, more severe course, and poor psychotherapy prognosis, which dampened this population’s treatment response [7].

Therefore, many countries, including South Korea, are scaling up national actions to prevent and respond to child maltreatment [3]. There is a consensus that child maltreatment is not a private but a societal issue, leading governments to invest more resources in strengthening legislative and supportive frameworks for abused and neglected children [3,5,8-10]. However, more attention is being paid to retributive justice by enforcing forensic investigations, child abuse offender punishment, or education. In contrast, implementing support systems for the psychological recovery of abused and neglected children is insufficient. Additionally, few countries are equipped with well-defined, measurable indices to identify problems and monitor and evaluate the effects of such efforts [3], which limits evidence-based approaches to enhance the effectiveness of prevention and service planning.

In fact, there are considerable individual differences in the psychological after-effects of maltreated children. As noted earlier, although child abuse victims are more vulnerable to diverse mental health problems, it is also true that not all abused children exhibit such problems [1]. Further, if any, they may present psychological problems of different profiles or severity. According to Korean government statistics [11], abused children under protection services reported multiple emotional and behavioral problems, including depression, anxiety, inattention/hyperactivity, violent behavior, and delinquency. However, these statistics were simple counts of the number of abused children relevant to each problem domain without utilizing standardized measures. The outcome domains were not exhaustive enough to encompass the psychological problems (e.g., PTSD symptoms) manifested in this group.

Research on the psychological aspects of abused Korean children is limited, and most studies have investigated abuse-related variables in the general child population. There is a paucity of research on maltreated children because they are vulnerable participants with limited access to individual researchers. The difficulty in obtaining parental consent for study participation complicates the matter, considering that most offenders are the parents themselves. To our knowledge, an exceptional study by Ha et al. [12] examined the prevalence of mental disorders in abused children (n=61, mean age=10.0, boys=62.3%) in Gangwon-do, South Korea. In this study, approximately half (45.9%) of the abused children reported no salient psychological problems. The other half (50.8%) were diagnosed with more than one mental disorder (attention-deficit/hyperactivity disorder, 23.0%; PTSD, 21.3%; depressive disorder, 16.4%; oppositional-defiant disorder 16.4%; conduct disorder, 8.2%), which was a much higher rate than that in the same age cohort (less than 8.0%).

Taking considerable heterogeneity into account, effective psychological intervention for maltreatment victims is possible only when their psychological state and the severity of problems are accurately assessed using reliable and valid measurement tools. Thus, developing a standardized and publicly available psychological scale with sound psychometric properties is essential to accumulating large-scale empirical data for evidence-based research and decision-making. A self-report scale is a viable option for this purpose. In general, self-reports have been widely utilized to screen high-risk groups requiring subsequent in-depth assessment or intervention, to measure symptom severity for treatment planning, and to monitor or determine the effect of treatment objectively [13]. Furthermore, they are convenient and cost-effective, as literate respondents (above 2nd or 3rd graders in elementary school) can comprehend and answer independently with minimal help, and scoring and interpretation are relatively straightforward compared to clinician ratings or interviews. Furthermore, self-report scales provide helpful information on the internal state of children (e.g., emotional state and self-perception) that cannot be fully captured through observation or parental reports [14,15]. Hence, if answered frankly, self-reports can serve as a valuable source of information to approach the subjective experiences of abused and neglected children, which cannot be overtly observed.

Although several self-report tools for children have been used in Korea, no single scale can comprehensively assess the vast array of psychological problems of maltreated children. Some widely-used self-reports focus on a specific topic—Korean Children’s Depression Inventory; 2nd Edition [16], Revised Children’s Manifest Anxiety Scale; 2nd Edition [17]. Among the self-reports assessing psychological trauma, the Trauma Symptom Checklist for Children [18], Children’s Response to Traumatic Scale; Revised (CRTES-R) [19], or the Child Report of Post-traumatic Symptoms [20] are validated into Korean [21-23]. Although these self-report scales are well-established tools, they do not provide comprehensive coverage of psychological problems relevant to child maltreatment with an economic number of items. In contrast, the Child Behavior Checklist [24] and the Korean Personality Rating Scale for Children (KPRC) [25] are well-known comprehensive problem behavior checklists usually administered as parent-report versions. However, these parent-reported scales are inadequate for capturing the subjective experiences of maltreated children. Furthermore, these scales are insufficient to address trauma, as none have been developed with a specific focus on assessing the psychological outcomes of child maltreatment. Additionally, most of these scales have copyright restrictions that limit their free use for public purposes.

Therefore, the present study primarily aimed to develop a self-report psychological scale that comprehensively evaluates emotional and behavioral problems and psychological trauma in abused children. Additionally, the newly developed scale was designed to include critical items (e.g., self-harm and suicide) for crisis intervention and an additional subscale of ego-resilience that acts as a protective factor. This multifaceted structure will increase its utility for multiple purposes, including screening, measuring symptom severity, and evaluating treatment effects.

The main purpose of this study was to develop and validate a standardized self-report questionnaire that comprehensively assesses emotional and behavioral problems and psychological trauma in maltreated children in Korea. In particular, it is worth emphasizing that this was the initial attempt to devise a comprehensive psychological assessment tool based on data collected from maltreated Korean children nationwide, while most previous studies translated questionnaires developed in other countries into Korean for validation purposes.

In this study, the MHS-MC demonstrated sound psychometric properties. The reliability ranged from good to excellent. Construct validity was supported by a five-factorial solution for depression, anxiety, inattention/hyperactivity/impulsivity, aggression/defiance, and psychological trauma in the CFA. Additionally, concurrent validity was confirmed in that higher total scores were associated with a significantly higher likelihood of allocation to the maltreated group than to the non-maltreated group.

The criterion-related validity was generally satisfactory, exhibiting significant correlations with relevant measures in the expected direction. Notably, the new scale had fewer items per subscale (10 items in the case of the five primary symptom subscales and only four items for the ego-resilience subscale), indicating that it can be an economical alternative with reduced time and effort on the part of the respondent. With broader coverage, this can be a practical strength for vulnerable participants, such as maltreated children. Moreover, the newly developed ego-resilience subscale showed a larger negative correlation with psychological trauma than the existing KPRC-ego-strength, which showed only a weak negative correlation. This may suggest that the new subscale items possess better validity as indicators of ego-resilience, which buffers against psychological problems after trauma exposure [37,38]. Altogether, the results demonstrated that the MHS-MC can be utilized as a reliable and valid self-report questionnaire for psychological assessment of maltreated children in Korea.

As previously mentioned, we are also aware of that there are other scales that either measure traumatic response of maltreated children, originally developed in the West, or measure mental health of general children. The comparative advantages of this newly developed MHS-MC can be summarized as follows. First, it can assess a wide range of psychological constructs that is particularly relevant to maltreated children; therefore, one can comprehensively measure the psychological profile of maltreated children with a single scale with an economic number of items. Second, the MHS-MC was developed for non-profit, public use in mind, different from other scales with copyright issues, which restricts their availability in public settings with limited budget. Therefore, the MHS-MC can be freely distributed nationwide and utilized as a publicly-available, standard measure of maltreated children without legal or financial concerns.

Furthermore, it is worth noting that the MHS-MC possesses a few important clinical and practical implications. First, the MHS-MC can be basically used to assess the current psychological state of maltreated children. Maltreated children may exhibit various psychological symptoms with differing profiles, depending on the individual and situation [1,39]. For example, some may have prominent complaints of emotional problems such as depression and anxiety, while others may display high levels of behavioral problems such as distractibility and/or aggression. Therefore, a comprehensive assessment covering a range of major domains is essential. In particular, results of this comprehensive assessment can point to domanis of interest for subsequent in-depth assessment and intervention planning tailored to individual needs of maltreated children.

Second, the MHS-MC will help judge the severity level of the psychological after-effects, including identifying high-risk groups in need of urgent intervention. Severity judgment can be critical, especially when public resources are prioritized. As described previously, two critical items—intention to self-harm/harm others and suicide—are included in the MHS-MC. Responses equal to or above 1 (somewhat) on any critical items were thought to signify that immediate intervention was necessary, regardless of the sum of the scores of other symptom subscales. Although approximate severity judgment is possible based on the relative standings of raw scores (e.g., Z score), a more valid interpretation would be feasible based on subscale and/or total scores if more data are accumulated to establish a representative norm in the near future.

Third, the MHS-MC would be utilized to evaluate treatment outcomes. This scale can be administered before and after a psychological intervention to assess the effect of psychological intervention and determine when to terminate. Several kinds of psychological interventions, such as trauma-focused cognitive behavioral therapy, are known to be effective for children with traumatic experiences, including childhood maltreatment [40,41]. Treatment outcome evaluation should be extensive, considering both symptom reduction and resource building. Naturally, the primary goal of treatment would be to alleviate distressing symptoms; however, bolstering coping resources would be equally essential to prevent the mental health problems of maltreated children in the long run [42]. Five symptom subscales of the MHS-MC comprise representative internalizing and externalizing symptoms in childhood and adolescence, while the complementary subscale of ego-resilience corresponds to coping resources. The multifaceted structure of MHS-MC makes it possible to address both sides of treatment outcomes.