I consider Attachment disorders as a subset of Personality disorders. Kurt Schneider described a number of these subsets. Therefore the therapeutic approach is the same.

Attachment disorders and personality disorders show significant overlap in their manifestations and underlying mechanisms (Brennan & Shaver, 1998; Beeney et al., 2015). Both involve difficulties in interpersonal relationships, emotion regulation, and self-perception (Bateman & Fonagy, 2004; Meyer & Pilkonis, 2005). Research indicates that insecure attachment styles are prevalent among individuals with personality disorders, particularly borderline personality disorder (BPD) (Mikulincer & Shaver, 2007; Bowlby, 1982).However, it's crucial to note that this question oversimplifies a complex relationship. Attachment problems are considered etiological factors, while personality disorders are the resulting psychopathology (Erikson, 1968; Sanislow et al., 2000). For instance, BPD is often viewed as a consequence of childhood neglect leading to insecure attachment (Lorenzini & Fonagy, 2013). This perspective aligns with the work of Karlen Lyons-Ruth, who has extensively researched the developmental origins of personality disorders (Lyons-Ruth & Brumariu, 2021).Lyons-Ruth's research suggests a developmental cascade model for BPD, linking early attachment experiences to later personality pathology (Lyons-Ruth & Brumariu, 2021). Furthermore, studies have shown that a history of abuse and punitive mother-adolescent interactions can mediate hostile-helpless attachment patterns in adolescents (Wells et al., 2023). Early maternal withdrawal has also been associated with developmental costs, highlighting the importance of early attachment experiences in shaping personality development (Lyons-Ruth & Yarger, 2022).While the connection between attachment disorders and personality disorders is strong, not all individuals with attachment issues develop personality disorders, suggesting additional factors are involved in their etiology.References:Bateman, A., & Fonagy, P. (2004). Psychotherapy for borderline personality disorder: Mentalization-based treatment. Oxford University Press.Beeney, J. E., Stepp, S. D., Hallquist, M. N., Scott, L. N., Wright, A. G., Ellison, W. D., Nolf, K. A., & Pilkonis, P. A. (2015). Attachment and social cognition in borderline personality disorder: Specificity in relation to antisocial and avoidant personality disorders. Personality Disorders, 6(3), 207-215. https://doi.org/10.1037/per0000110Bowlby, J. (1982). Attachment and loss: Vol. 1. Attachment (2nd ed.). Basic Books.Brennan, K. A., & Shaver, P. R. (1998). Attachment styles and personality disorders: Their connections to each other and to parental divorce, parental death, and perceptions of parental caregiving. Journal of Personality, 66(5), 835-878. https://doi.org/10.1111/1467-6494.00034Erikson, E. H. (1968). Identity: Youth and crisis. W. W. Norton & Company.Lorenzini, N., & Fonagy, P. (2013). Attachment and personality disorders: A short review. FOCUS, 11(2), 155-166. https://doi.org/10.1176/appi.focus.11.2.155Lyons-Ruth, K., & Brumariu, L. E. (2021). Emerging child competencies and personality pathology: Toward a developmental cascade model of BPD. Current Opinion in Psychology, 37, 32-38. https://doi.org/10.1016/j.copsyc.2020.07.004Lyons-Ruth, K., & Yarger, H. A. (2022). Developmental costs associated with early maternal withdrawal. Child Development Perspectives, 00, 1-8. https://doi.org/10.1111/cdep.12442Meyer, B., & Pilkonis, P. A. (2005). An attachment model of personality disorders. In M. F. Lenzenweger & J. F. Clarkin (Eds.), Major theories of personality disorder (2nd ed., pp. 231-281). Guilford Press.Mikulincer, M., & Shaver, P. R. (2007). Attachment in adulthood: Structure, dynamics, and change. Guilford Press.Sanislow, C. A., Grilo, C. M., & McGlashan, T. H. (2000). Factor analysis of the DSM-III-R borderline personality disorder criteria in psychiatric inpatients. American Journal of Psychiatry, 157(10), 1629-1633. https://doi.org/10.1176/appi.ajp.157.10.1629Wells, J., Knoll, M. A., Lyons-Ruth, K., & Obsuth, I. (2023). History of abuse and adolescent hostile-helpless attachment: The mediating role of mother-adolescent punitive interactions. Child Abuse & Neglect, 140, 106190. https://doi.org/10.1016/j.chiabu.2023.106190