Abstract
Objectives. This study is aimed at testing and validating the two-factor measurement model of the Millon Clinical Multiaxial Inventory (MCMI). Specifically, this paper reported construct validity, particularly focusing on convergent and discriminant validities of the internalizing-externalizing MCMI model of adult psychopathology using a psychiatric sample from a developing country, the Republic of Yemen. Methods. MCMI was distributed among 232 outpatients from the Hospital of Taiz City and two private psychiatry clinics in Yemen; data were collected using structured interviews over four months. We used exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) to explore and confirm the latent structure MCMI and verify the evidence of convergent and discriminant validity. Results. The CFA results indicated that MCMI was a good fit for the internalizing-externalizing two-factor model of adult psychopathology, comparative fit index , and . The results of the CFA provide evidence of convergent and discriminant validity characterized by MCMI with the internalizing-externalizing model. Conclusion. The adult psychopathology of internalizing-externalizing is a valid measurement model of MCMI with ten personality disorders and eight clinical syndromes.
1. Introduction
Children’s behavioral issues are now conceptualized differently by researchers, clinicians, and educators as a result of Achenbach’s original findings on childhood psychopathology assessment [1, 2]. One of the fundamental aspects of the analyses is the hierarchical conceptualization of mental disorders in terms of two broad behavioral spectra, which Achenbach termed internalizing and externalizing. The spectra accounted for the systematic covariation among more narrowly defined behavioral problems [3]. Internalizing problems in childhood include anxiety, depression, and somatization-based disorders while externalizing problems include behavioral misconduct, anger, and attentional difficulties [2].
Another contribution of Achenbach’s work is its impact on approaches to conceptualizing adult psychopathology [4]. As a potential theoretical framework for organizing the structure of adult mental disorders, this internalizing-externalizing model has received a significant amount of attention [4–6]. Internalization is the propensity to express distress inwards; common internalizing disorders include major depression, dysthymia, generalized anxiety disorder, agoraphobia, social phobia, simple phobia, and obsessive-compulsive disorder. Conversely, externalization describes the propensity to express distress outwards; commonly recognized externalizing disorders include conduct disorder, antisocial personality disorder, marijuana dependence, and alcohol dependence [7–20].
The internalizing-externalizing spectra have been proposed as an organizational system applied in DSM-5 [5]. Regarding this change, several advantages have been highlighted, including the use of a more parsimonious and meaningful organizational model/schema, the ability to simplify problems caused by excessive comorbidity, aiding intervention and treatment development, and creating an important area for future research [6, 8, 21–23]. This internalizing-externalizing framework has been demonstrated across multiple disorders [17, 24], genders [25, 26], ethnicities [26], cultures [10], and over time [7]. It has also been highly successful in accounting for the relationships between psychopathology and other constructs [27] in explaining the etiology of psychopathology in twins’ studies [28, 29] and in studying adults with attention-deficit/hyperactivity disorders (ADHD) [30]. Although there is growing recognition that comorbidity among individual mental disorders is better understood by the broad psychiatric dimensions of internalization and externalization, expanding the scope of this framework is still needed [12, 24].
Previous studies indicated that the internalizing and externalizing spectra capture much of the genetic vulnerability to common mental disorders [31, 32]. In a severely extremely sick cohort, Kotov et al. [33] study also supported the essential internalizing-externalizing concept. These spectra seem to be comparable across cultures, ages, and inpatient samples. This knowledge can be useful because the new classification promises to improve our understanding of psychopathology in a variety of ways. However, assessments of internalizing-externalizing difficulties were based on ad hoc questions, scales, or scale combinations that were unique to each study. It is recommended to recognize that internalizing and externalizing problems are not mutually exclusive or completely independent of one another but are moderately correlated in many samples. Assessments of broadband problem groups, narrow-band syndromes, and individual problems can all be valuable for early clinical evaluation progress, outcome evaluations, and research on etiologies, treatments, outcomes, and epidemiology [34].
The Hierarchical Taxonomy of Psychopathology (HiTOP) is a scientific effort to address shortcomings of traditional mental disorder diagnoses, which suffer from arbitrary boundaries between psychopathology and normality, frequent disorder cooccurrence, heterogeneity within disorders, and diagnostic instability [33, 35–38]. The Hierarchical Taxonomy of Psychopathology (HiTOP) is a new classification of mental illness. It aims to address several major shortcomings of traditional taxonomies and provide a better framework for researchers and clinicians.
The HiTOP model included six spectra: internalizing (or negative affectivity), thought disorder (or psychoticism), disinhibited externalizing, antagonistic externalizing, detachment, and somatoform. Given the direct correspondence between internalizing and negative affectivity as well as between thought disorder and psychoticism, each of these pairs is represented by one dimension. Externalizing behavior has two personality counterparts: disinhibition and antagonism. Disinhibition is particularly prominent in substance-related disorders, and antagonism is especially significant in narcissistic, histrionic, paranoid, and borderline PDs. Both disinhibition and antagonism contribute to antisocial behavior, aggression, ODD, ADHD, and IED [33, 35–43].
