Toward a multidimensional, psychodynamic and empirically-supported diagnosis of eating disorders: implications for the PDM-3

Abstract (max 1.000 parole) Introduction: To date, the tendency to adopt a primarily rigid, categorical, and symptom-oriented diagnostic model of eating disorders (ED) has likely hindered the progression of both clinical and scientific knowledge about their etiology, onset, course, maintenance, clinical presentation, and recovery rates. Moreover, most practice guidelines on ED treatment agreed that there should be a continuum of care, in which interventions should be chosen according to a comprehensive understanding of the ED patients’ individual and trans-diagnostic characteristics, such as personality functioning. The second edition of the Psychodynamic Diagnostic Manual (PDM-2; Lingiardi & McWilliams, 2017) offers a complementary perspective to the descriptive systems of the DSM and ICD, promoting a diagnostic approach to ED that is not only symptom-oriented but also devoted to individuals’ idiographic, subjective characteristics and psychological functioning. The main aim of this study was to explore whether ED-specific symptomatology, body uneasiness and dissatisfaction, and global psychopathological impairment at treatment intake could be predicted by the assessed dimensions of the PDM-2, with a specific focus on personality organizations, severity of personality pathology, and mental functioning dimensions. Methods: A national sample of cisgender women with an eating disorder (ED) (N= 97) was evaluated using both the Structured Clinical Interview for DSM-5 (SCID-5-CV) and the Psychodiagnostic Chart-2 (PDC-2)—a PDM-2 derived clinician-rated tool. Participants were also asked to complete self-report questionnaires on ED symptomatic impairment (Eating Disorder Inventory-3, EDI-3), body uneasiness (Body Uneasiness Test, BUT) and overall psychopathological symptoms (Outcome Questionnaire 45.2, OQ-45.2) at treatment intake. The inclusion criteria were: (a) aged at least 18 years; (b) a pre-treatment diagnoses of DSM-5 anorexia nervosa (AN) or bulimia nervosa (BN) posed by a licensed staff psychologist or psychiatrist and based on the SCID-5; (c) presenting no organic syndromes, psychotic disorder, or syndrome with psychotic symptoms that could complicate the assessment of any variable in the study. In the present sample, N = 54 patients were diagnosed with AN, and N = 43 received a BN diagnosis. No limits were applied to the body mass index (BMI) at the admission. Treatment was provided in a multidisciplinary, psychodynamic-oriented residential setting and consisted in individual weekly psychotherapy sessions, encounters with specialized social workers, and sessions with a nutritional physician. Results: Findings showed that patients with AN and BN, as diagnosed by the SCID-5, did not significantly differ either in overall personality organization and personality organization’s dimensions (P Axis) except for the maturity of defenses, with lower levels of defensive functioning in BN patients. Similarly, patients with AN and BN did not show differences in mental functioning capacities (M Axis) or symptomatic impairment (S Axis), whereas BN patients showed lower levels in the M Axis capacity for impulse control and regulation. With respect to ED-related symptoms and P Axis dimensions, the quality of object relations, reality testing, and overall personality organization showed negative associations with overall ED symptomatology, whereas severity of personality pathology showed positive associations. However, only overall personality organization and severity of personality pathology emerged as significant predictors. Further on, among those M Axis dimensions which showed negative associations with ED symptoms, reflective functioning, differentiation and integration (identity), impulse control and regulation, and overall mental functioning predicted EDI-3 overall score, along with S Axis severity of symptomatic impairment. With respect to body uneasiness, our results showed that P Axis reality testing and overall personality organization predicted BUT Global Symptomatic Index (GSI), along with the M Axis reflective functioning, differentiation and integration, psychological mindedness, and overall mental functioning. Interestingly, both P Axis reality testing and M Axis reflective functioning also showed negative associations with all BUT subscales (i.e., Weight Phobia, Body Image Concerns, Avoidance Compulsive Self-Monitoring, and Depersonalization). Lastly, P Axis object relations and overall personality organization, M Axis affective functioning, impulse control and regulation, and overall mental functioning, and S Axis symptomatic impairment have been found to predict OQ-45.2 overall score at treatment intake. Conclusion: These findings may have several implications in the future ED conceptualization in the PDM-3. First, they suggest that, over and above the DSM-based categories, the S Axis works jointly with the P and M Axes to create a comprehensive representation of the psychological and/or psycho-pathological functioning of ED patients. Thus, the S Axis provides only one of three crucial perspectives on the person and assists clinicians in creating a multifaceted diagnostic profile of ED to develop a case formulation that allows an effective and patient-tailored treatment planning (Muzi et al., 2021; Mundo et al., 2018). Further on, our results suggest that body uneasiness and dissatisfaction are key features in eating pathologies as a potential trans-diagnostic target for treatment (Moccia et al., 2022). Then, bodily experiences could be further described in the future ED description in the S Axis, along with a potential inclusion of this dimension within the M Axis capacities. Accordingly to previous studies (e.g., Westen & Harnden-Fischer, 2001), these findings also suggest the need to take into account the high heterogeneity of ED clinical presentations and to consider personality organization and mental functioning as potentially stable variables that should be routinely assessed at treatment intake and included in case conceptualizations. In sum, the PDM-3, as its predecessor, should further enhance a person-centered ED diagnosis, including specific transdiagnostic characteristics (e.g., personality features; body dimensions) of individual patients in order to better meet their needs and enhance their therapeutic outcomes.