Personality Disorders and Attachment Trauma in Adolescent Patients with Psychiatric Disorders

Over the years, several studies suggest that the diagnostic features related to personality disorders (PD) are relatively stable in adolescent age groups (Chanen, 2022; Chanen & Thompson, 2018) and they support the idea that all PD types can also be identified in adolescents (Westen et al., 2014). Nevertheless, the stability of PD in younger age groups remains a contentious topic for debate (d’Huart et al., 2022). Morey and Hopwood (2013) outline that temporal stability of PD is considered as a complex notion and depends on clinical status and age range of the sample as critical factors in affecting the stability of PD over time. Existing findings, however, demonstrate that the stability of PD in adolescent age groups is found to be similar to the stability reported in adults (Grilo et al., 2001; Sharp & Wall, 2018).

Clinicians argue that an early detection and intervention in adolescent patients with PD is crucial for preventing adverse outcomes (Biberdzic et al., 2022). Evidence from a growing body of research shows that adolescent patients with a PD have elevated levels of psychopathological symptoms, a higher suicide risk, early onset-substance abuse, a lower quality of life, higher drop-out rates from education, an increased risk of being the victim or perpetrator of family violence and a poor physical and sexual health (Chanen et al., 2020). Furthermore, the presence of a PD is the fourth leading cause of disability among mental disorders, also in younger age groups < 18 (Mental Disorders Collaborators, 2022). Given that PD are among the most prevalent mental disorders in community samples with up to 10% (Winsper et al., 2020) and even rates up to 50% in clinical samples (Tyrer et al., 2015), they should be recognized as an important contributor to mental health and disease burden also in younger age groups. Several researchers emphasize that the economic burden is particularly high for patients with PD. This burden is much higher compared to help-seeking individuals with other mental disorders like anxiety disorders or major depression (Soeteman et al., 2008). Hastrup et al. (2019) highlight in their study that the annual total costs for patients with Borderline PD (BPD) were 16 times higher compared to matched controls without a BPD. The higher costs were observed particularly during the 5 years before they received a BPD diagnosis. Inpatient psychiatric treatment made up over 50% of the total costs. Moreover, spouses of patients with BPD demonstrated increased health care costs and significant productivity loss which present a further argument in favor of an early diagnosis and disorder-specific treatment.

While international classificatory systems might have expressed some caution to diagnose PD in patients below the age of 18 in the past, DSM-5 and ICD-11 have removed age-related caveats on the diagnosis of a PD based on the vast scientific evidence supporting an early diagnosis (Chanen, 2022). This vital reform to child and adolescent psychiatry and mental health sets the ground for further research on the pathogenesis, course and effective intervention for this group of young people who are at a high risk for adverse consequences in life. Studies in adolescent psychiatric samples are still rare.

Concerning the prevalence rate of PD in males and females, study results from adult samples are inconsistent. Some found a higher prevalence in males and described them as showing more externalizing symptoms, comorbid substance abuse and impulsive behaviors than females with PD (Amerio et al., 2023; Huang et al., 2009). Other researchers report higher levels of PD in females (Björkenstam et al., 2015) with the BPD as the most common one (Amerio et al., 2023). However, gender differences in adolescent PD have not yet been completely explored. Relevant literature in clinical and non-clinical settings is still scarce. For example, Mar et al. (2023) recently published a population-based study on the incidence of mental disorders and they report a higher incidence of PD in males particularly in the third decade of their life. In one of the only studies in hospitalized adolescent patients, females show higher rates of BPD, whereas males had higher rates of narcissistic PD but no gender differences were found for the other PD (Grilo et al., 1997). Although there are a handful of studies focusing on gender differences in the clinical presentation of BPD in adolescents (i.e. Bradley et al., 2005), prevalence rates regarding gender differences in adolescents with one or more PD in inpatients are still missing.

Furthermore, factors contributing to early manifestation of PD in adolescent psychiatric populations are still poorly understood. Childhood trauma and attachment are two important components that are considered to play a central role in the pathogenesis of PD.

Studies in adult psychiatric patients show that childhood maltreatment might be an important risk factor for the onset of personality pathology in adults (Buchheim et al., 2008; Kounou et al., 2013). In particular, individuals who experienced emotional neglect and abuse as well as physical abuse presented more severe PD symptoms compared to individuals without childhood trauma (Kounou et al., 2013; Wang et al., 2022). For adolescents, the majority of data is based on studies in younger patients with borderline features (Chanen & McCutcheon, 2013; Ibrahim et al., 2018; Sharp & Fonagy, 2015). This research suggests that all types of neglect and abuse were related to borderline features (Ibrahim et al., 2018) and more types of abuse were associated with increased levels of borderline features (Hecht et al., 2014) in younger populations. Nevertheless, traumatic childhood experiences are considered as non-specific risk factors for PD (Paris et al., 2014). Yet it is still unclear how these experiences might be related to adolescent PD. Furthermore, the majority of research is limited to the use of self-report measurements like the Childhood Trauma Questionnaire (CTQ, Bernstein & Fink, 1998) that retrospectively assess subjectively reported adverse childhood experiences. Although this measure is one of the most commonly-used and well-validated instruments in adolescent and adult populations, it has often been criticized because it is a retrospective self-assessment tool that includes the potential for recall bias (i.e. underreporting adverse childhood experiences due to feelings of shame and fear of stigmatization, depending on an individual’s memory performance and motivation to recall these experiences etc. (Wente et al., 2023). Given that PD are linked to enduring patterns of interpersonal functioning and emotion regulation (Hengartner et al., 2015; Nakash-Eisikovits et al., 2002) attachment theory might offer a conceptual bridge between these two components.

Concerning attachment patterns, associations between insecure-dismissing, insecure-preoccupied and unresolved attachment patterns and PD have been explored by research using various methodologies (Levy et al., 2015; Mikulincer & Shaver, 2016). Many studies on PD use attachment questionnaires evaluating an individual’s conscious thoughts about his or her attachment to significant others. This approach allows assessing attachment styles to a number of different caregivers (Roisman et al., 2007) and was used in several studies on adolescent personality pathology) and intervention studies, particularly in the field of dialectic behavioral therapy (DBT, (Bernheim et al., 2019) and mentalization-based therapy (MBT, (Cooper et al., 2021; Beck et al., 2016). However, questionnaires cannot assess unconscious aspects of attachment-related defenses and behaviors. Attachment interview procedures like the Adult Attachment Interview (AAI, (George et al., 1996) or the Adult Attachment Projective Picture System (AAP, (George & West, 2012) focus on mental representations of attachment by evaluating patterns of responses when participants talk about attachment situations. These interviews can classify attachment disorganization and trauma (George & Buchheim, 2014; George & West, 2012). The conceptual difference to childhood maltreatment assessed with a self-report questionnaire like the CTQ is that the disorganized-unresolved attachment pattern refers to the attachment disorganization and fear when confronted with attachment-related situations that represent a severe threat to the self (i.e. loss, separation, danger). In these situations, individuals need an attachment figure that provides comfort and safety. However, they experienced attachment figures that were unable to provide safety and help them to sooth their hyperarousal and thus they could not integrate traumatic attachment-related experiences. Hereby, the traumatic element is defined as the personal experience of a caregiver’s failure to respond sensitive to the needs of an individual during moments of severe attachment-related distress and threat which leads to feelings of helplessness, isolation and being caught in these experiences (Gander et al., 2018a; Zilberstein, 2014). Although some researchers refer to the “unresolved-disorganized attachment status” (i.e. van Hoof et al., 2019) in younger age groups, we use the term “unresolved attachment” which is commonly used in adolescent and adult age groups in the present study (Gander et al., 2021; Gander, Sevecke Gander et al., 2018a, b).

A large research base using narrative attachment measurements indicates that the unresolved classification predominates in adult patients with severe mental disorders, especially in those with PD (Beeney et al., 2017; Buchheim et al., 2017; Gander et al., 2018b; Levy, 2005; Nakash-Eisikovits et al., 2002). In the empirical literature on attachment much emphasis is given to adult patients with borderline PD (Buchheim & Diamond, 2018; Hengartner et al., 2015). Taken together, these studies demonstrate that an insecure and unresolved attachment quality is significantly linked with the severity of borderline symptoms in adolescence (Ibrahim et al., 2018; Sharp & Fonagy, 2015; Whalen et al., 2014). Additionally, studies have demonstrated a remarkable negative predictive value of a secure attachment pattern for any PD (Hengartner et al., 2015; Nakash-Eisikovits et al., 2002).

Despite robust evidence indicating a high prevalence of the unresolved attachment status in adults with PD, current research still lacks data on attachment representations in adolescents with a diagnosed PD. There are some recently published studies that focus on attachment and impaired personality functioning. In this context, childhood maltreatment was shown to represent an important risk factor for maladaptive personality functioning in adolescence. However, not all of them develop personality pathology (Paris et al., 2014). Luyten and Fonagy (2020) suggested that the unresolved attachment might play an important role for the link between childhood trauma, intrapersonal and interpersonal functioning. They propose that unresolved individuals with abusive or neglecting attachment figures might feel trapped in an approach-avoidance conflict. This conflict is expressed in the idealization-denigration cycles in their relation to other individuals. That is, they might perceive both the self and others as either extremely positive or as extremely negative depending on the situation. As a consequence they might feel confused regarding their self and the others - a characteristic that is commonly observed in traumatized adult patients with borderline PD (Luyten et al., 2020). Thus, traumatized individuals classified with an unresolved attachment pattern might have problems in developing a feeling of self-coherence and self-continuity as well as relatedness to others which are considered as core aspects of PD (Luyten et al., 2020). A study by Gander et al. (2020) could provide support for this conceptual bridge between attachment and trauma for the first time in younger age groups. They found that adolescents with a high amount of attachment trauma showed a lower resilience when facing traumatic childhood experiences resulting in greater impairments in personality functioning.

Even though research demonstrates important links between attachment experiences, childhood trauma and personality pathology, these results draw heavily from adult samples. Furthermore, many findings were based on patients with Borderline PD and did not include patients with other PD. As researchers progress towards creating an etiological model of adolescent PD, it is important to conduct research that incorporates adolescent patients who have been diagnosed with one or more PD. Although several research studies and the current classification systems DSM and ICD emphasize that most PD take their onset in adolescence and persist into adulthood, it is still unclear if patients with an adolescent onset differ from those with an onset in adulthood. There are a handful of studies comparing adolescent and adult samples with BPD suggesting that adolescents show similar neurobiological markers and interactions between temperament and adverse life events than those reported in adult samples with BPD (Paris, 2013). However, there is a lack of research on the role of trauma, particularly attachment-related trauma, in adolescents with PD.

In addition, attachment-related differences between adolescent inpatients with and without PD have not been addressed yet. In this context the Adult Attachment Projective Picture System (AAP, (George & West, 2012) has often been used as a viable tool to investigate the underpinnings of unresolved attachment in abnormal child development (Buchheim et al., 2008; Gander et al., 2020, 2021; Gander, Sevecke et al., 2018). This instrument allows for subjects to reveal traumatic material that indicates attachment-related danger or fear and has successfully been implemented in the field of adolescent psychiatry (Gander et al., 2020, 2021; Gander, Sevecke et al., 2018; Lenhart et al., 2022). Since PD are often discussed to be a consequence of disturbing attachment experiences, this approach might deepen our understanding of PD in youth.

This study examined the prevalence of PD in an adolescent psychiatric inpatient sample and found that 22% of our adolescents fulfilled the criteria for one or more PD. We did not find any sex differences for PD. This is the first study demonstrating that adolescent patients with PD have a higher amount of unresolved attachment patterns. Our in-depth analysis revealed that they had more traumatic material in their attachment narratives indicating a greater severity of attachment trauma. In particular, the theme of constriction left them in a state of dysregulation. In the AAP constriction refers to a condition in which patients freeze or are totally blocked from completing the attachment interview because their attachment-related defenses and resources break down and attachment-related fears become too overwhelming. In patients with PD this more often occurred in response to dyadic picture stimuli that depict elements of the caregiving relationship. Furthermore, patients with PD demonstrated higher scores on subjectively reported emotional and physical neglect in their childhood. Our findings might have important implications for the treatment of young people with PD.

Our results on prevalence rates of PD in adolescent inpatients is higher than rates reported in adult community samples (Winsper et al., 2020) but lower than rates reported in some adult clinical samples (Tyrer et al., 2015). Plausible explanations for these findings are rooted in the heterogeneity across studies. That is, some traits and categories might not be equally valid in different countries, variations in behavioral norms can have an influence on the PD prevalence rate and possible impacts of culture, race and ethnicity on PD specifically are still poorly understood (Winsper et al., 2020). Furthermore, the breadth of definition is crucial in determining accurate prevalence rates (Beckwith et al., 2014). We used the SCID-II interview that assesses moderate to severe PD; however, it does not include mild forms of PD which might explain why we found a lower rate compared to other studies. A study by Newton-Howes et al. (2010) demonstrates that exclusion of PD not otherwise specified and mild forms let prevalence rates drop from 40 to 10% in clinical samples.

Concerning the subtypes, our results demonstrated a relatively high rate of avoidant PD in adolescents. One reason for this finding might be the high prevalence of depressive disorders and Anorexia Nervosa (restrictive type) in our adolescent inpatient sample. Despite the fact that studies in clinical samples report higher rates of borderline PD (Sharp & Fonagy, 2015), our results are in accordance with data in adolescent and adult samples showing a high proportion of avoidant PD particularly in Anorexia Nervosa and depression (Magallón-Neri et al., 2014; Rotella et al., 2016).

In regard to gender differences, research points out that PD are equally common in both males and females; however, in clinical groups some studies report higher proportions of women with PD probably due to a greater help-seeking behavior, particularly in those with Borderline PD (Björkenstam et al., 2015). Interestingly, we could not replicate this finding in younger populations. This finding is partly consistent with some studies conducted in adults with PD. However, more large-scale research is needed in adolescent psychiatric populations (Conway et al., 2017) before strong conclusions can be drawn regarding the prevalence rates and sex differences. Additionally, generalization on gender differences should be treated with caution as they might be limited to our sample characteristics.

Concerning attachment patterns, half of our sample was classified with an unresolved attachment status. Although the high rate of this attachment pattern was also found in other studies in adolescents (Gander et al., 2021) and adults (Bakermans-Kranenburg & van IJzendoorn, 2009), the study of Venta et al. (2014) found a relatively low prevalence rate of 17% of unresolved individuals in their inpatient adolescent sample. One reason for these discrepancies might be the heterogenous diagnoses in inpatient samples. Whereas almost 50% of the Venta et al. (2014) study were diagnosed with an obsessive-compulsive disorder and oppositional defiant disorder which might be associated with a lower number of unresolved classifications, our sample consisted of patients with severe eating disorders and major depression – disorders more commonly associated with higher rates of unresolved attachment patterns (Delvecchio et al., 2014; Gander, Sevecke et al., 2018).

A major finding of this study was that adolescent patients with a PD demonstrated a higher amount of the unresolved attachment status and a higher severity of attachment trauma. This result corroborates previous research, particularly in the field of adult borderline PD (BPD) (Nakash et al., 2021). BPD is characterized by difficulties in the concept of the self, affect regulation, self-harming behaviors and episodic aggression. These problems in individuals with BPD manifest most prominently in interpersonal contexts (Weinstein et al., 2014) and they clearly resemble the contradictory and disoriented behaviors observed in disorganized infants (Beeney et al., 2017). Attachment theorists have already proposed that the unresolved attachment status provides a fertile ground for the onset of personality pathology (Buchheim & Diamond, 2018; Buchheim et al., 2017; Levy et al., 2015; Weinstein et al., 2014). Unresolved states of mind are associated with an individual’s perception of being abandoned and alone due to the failed protection by attachment figures. This experience of persistent dysregulated fear leads to the perception of an inner world that is characterized by incoherence, helplessness, isolation and chaos and threatens an individual’s psychological safety and self-integrity (Gander, Sevecke et al., 2018; George & West, 2012). This might result in severe intra- and interpersonal difficulties that are consistent with the disturbances observed in PD (Levy et al., 2015). The higher amount of traumatic attachment-related material in the narratives of our adolescent patients with PD compared to those with no PD provides additional support for this theoretical link. Furthermore, our in-depth analysis revealed that adolescent patients with PD show a lot of traumatic material in stories depicting interpersonal relationships. They were more often totally blocked from telling the story which might be indicative of their failure to contain the breakthrough of painful memories and attachment-related fears (George & West, 2011). In the story-telling process this becomes evident when individuals hand the picture back to the interviewer and make a statement that they are not going to respond to the stimulus or continue the story (i.e. I feel something coming, I really don’t want to say something; it is the kind of scene I refuse to live, I don’t want to verbalize on this; I don’t want to do this one, that is enough) (George & West, 2012). These findings indicate that interpersonal problems like impairments in empathy, reciprocity and attachment are at the core of personality dysfunction not only in adults (Hengartner et al., 2015) but in adolescents as well. In this context, our study retains a dimensional assessment of attachment by assessing the amount of traumatic material related to attachment. This is considered as a useful new approach in exploring attachment-related issues. Other authors who use the Child Attachment Interview use the dimensional scale of coherence (i.e. fresh speech, consistency, reflectiveness, comprehensibility, narrative production etc.) as an index of attachment disorganization (Sharp et al., 2016). However, the AAP does not assess coherence of the narratives so that the approach that is opted by Sharp et al. (2016) could not be applied to our study design. Furthermore, although Sharp et al. (2016) used the coherence of the narrative as an index of attachment disorganization, high scores on this scale are considered to be indicative of a lot of idealization and anger – typical features related to the insecure-dismissing and the insecure-preoccupied type (George & West, 2011). Thus, low coherence scores might not automatically be related to severe disorganization but can also be a characteristic of insecure but “resolved” individuals. Nevertheless, this approach might be an interesting direction for future research in adolescents with a diagnosed PD.

Concerning childhood maltreatment, patients with PD demonstrated moderate to severe scores on emotional abuse and neglect and moderate scores on the other childhood maltreatment experiences. These findings are in line with current findings demonstrating a link between traumatic experiences in childhood and personality pathology (Wang et al., 2022; Wong et al., 2022). In patients with BPD, researchers found that an exposure to different types of childhood trauma (i.e. emotional neglect and abuse, sexual and physical abuse) is associated with an increased risk for borderline symptoms in late childhood and adolescence (Ibrahim et al., 2018; Luyten, 2017). Even though numerous cohort studies suggest a strong link between childhood maltreatment and a wide range of adverse psychological symptoms (Wang et al., 2022), our results demonstrate that adolescent inpatients with PD report higher scores on emotional and physical neglect compared to those with no PD. In this context, attachment theory might offer a comprehensive view on underlying mechanisms that put adolescents at risk for an early onset of PD in response to these experiences. Researchers found that these types of trauma typically occur in the context of familial neglect and maltreatment (i.e. mental disorders in parents, poor parenting experiences) (Luyten, 2017). Given that the social proximity and prompt responsiveness of attachment figures are important for affect regulation difficulties in those with a PD (Hengartner et al., 2015), affect regulation deficits might become apparent in the face of traumatic childhood experiences (Bizzi et al., 2015). Patients with an unresolved attachment status are often incapable of tolerating their inner mental states and successfully regulate intense emotional states in response to maltreatment because of their lack of resources that provide attachment security (George & West, 2012). Instead, they remain in a state of dysregulation characterized by feelings of being trapped, isolated and helpless. This might lead to severe impairments in the domains of personality functioning. Gander et al. (2020) undermine this assumption by showing that adolescents with an unresolved attachment status report a lack of emotional self-experience and stabilizing perspectives, inconsistent self-images, a lack of autonomy and severe interpersonal problems. Thus, the quality of attachment might be an important factor involved in the onset of personality pathology in adolescence, particularly for those experiencing severe emotional and physical neglect in their childhood.

Interestingly, our patients with PD demonstrated less minimization of childhood maltreatment. This might be explained by the high proportion of patients with severe Anorexia Nervosa in our study sample. Some studies could show that these patients reach higher scores on the minimization/denial scale in the CTQ compared to other clinical groups (Couturier & Lock, 2006; Gander, Sevecke et al., 2018). Researchers argue that the denial of interpersonal difficulties and ruptures in parent-child relationships might represent a form of self-protection so that patients with Anorexia Nervosa do not have to communicate their inner feelings towards others. On the other hand, patients with PD are more likely to report childhood maltreatment (Wang et al., 2022); however their poor insight into their emotions, thoughts and psychological processes related to their childhood trauma as well as their low levels of self-regulation capacities (Goodarzi et al., 2018) might be related to severe intra- and interpersonal impairments.

The findings of the present study have to be interpreted in the context of some limitations. First, our adolescent inpatient sample consists largely of middle-class subjects with a relatively homogenous educational level and limited cultural diversity. Even though these sociodemographic variables are not related to attachment classifications (Gander et al., 2017), our results should be replicated in adolescent samples with other sociodemographic backgrounds. Furthermore, we only included psychiatric inpatients that might demonstrate a higher symptom severity and higher comorbidity than outpatient samples and we had a higher proportion of females. This is not unusual in research conducted in inpatient psychiatric samples due to the gender gap in mental health service use as men are reported to make fewer visits to mental health specialists than women (Pattyn et al., 2015). However, future studies might do well to conduct attachment, PD and childhood maltreatment in in- and outpatient adolescent samples with similar numbers of males and females. Second, our findings are based on a single point in time which increases the likelihood of method bias. In particular, we did not evaluate traumatic childhood experiences across developmental periods. This approach would allow an in-depth perspective on the cumulative effect of childhood maltreatment on adolescent personality pathology (Hecht et al., 2014). In this regard, the majority of our sample was assessed before the COVID pandemic so our data might not be generalized to prevalence rates during the pandemic years. Furthermore, the physical neglect subscale demonstrated the lowest internal consistency among all subscales of the CTQ which is in line with many previously published studies (Peng et al., 2023). Therefore, researchers suggested to re-examine or modify the items of this subscale and combine the physical and emotional neglect into one neglect scale in future research studies. Third, we used the SCID II interview to assess personality disorders on a categorical level. In this regard, future research should conduct a detailed analysis on attachment-related aspects for each PD. However, in our sample 20% of patients fulfilled the criteria for more than one personality disorder (some even up to 4 PDs according to the SCID-II interview). Although attachment-related differences among the different PD categories might be interesting venue for future research, our data suggests that in clinical practice some adolescents might show pathological scores in more than one PD. Similar findings of this overlap of PD facets have been reported in previous samples in adults as well, particularly in those with severe PDs, and thus represents a major limitation of the categorical model of PD. As PDs might not be best understood in terms of unique and nonoverlapping categories, a dimensional model of PD is supported which focuses on impaired levels of personality functioning that seems to be common to all PD types. Evidence for this theoretical framework stems from a recently published study by Simon and Bach (2022). Their analysis in a large clinical adult sample demonstrate that ICD-10 categorical PDs can be organized according to the four levels of ICD-11 dimensional PDs. In other words, their findings suggest a conceptualization of familiar PD categories in terms of ICD-11 PD severity and vice versa. Based on these results, creating one category for all PDs might represent an interesting approach as they all share impairments in the levels of personality functioning. Nevertheless, our approach does not come without conceptual and methodological limitations that need to be studied in future research.

Latest research in the field highlights the importance of using a dimensional approach of PD. Therefore, future research should additionally use validated measures that allow assessing DSM 5 PD on a dimensional level (Furnham et al., 2014). Although an alternative model for diagnosing PDs dimensionally has been integrated into the DSM-5 section III, the categorical definition of PDs has not been changed from the DSM-IV-TR. Thus, the categorical classification represents the main diagnostic guideline for all health care professionals in the U.S. including child and adolescent psychiatrists. Due to the aforementioned overlap of symptoms in our sample, studying symptom counts in larger samples might be an interesting approach for future research. Our research team is currently conducting a study on attachment and the dimensional classification of PD to explore whether we can replicate these findings using the new classification criteria in adolescents.

Fourth, as our sample size for each diagnostic subgroup was modest in our adolescent sample, our data did not allow analyzing potential effects of comorbid symptoms on the various measures. Yet more research focusing on comorbid disorder-specific aspects related to childhood maltreatment and attachment in adolescent patients with PD is needed before conclusions can be drawn in this field. In this context, a dimensional approach on impaired personality functioning might be a good alternative to expand our understanding of comorbid PD in mental disorders.

A fifth limitation is that a differentiation between all 4 attachment groups would do more justice to the differences between patients with and without PDs. However, in our inpatient clinical setting the low number of secure individuals did not allow a statistic analysis of the four attachment patterns. Furthermore, our approach is in line with other research studies that used the two-group classification of attachment which is a common method to distinguish between those with and without attachment trauma, i.e. individuals who can regulate and adapt to attachment-related stressors vs. individuals who dysregulate or become overwhelmed by traumatic attachment-related experiences (Gander et al., 2021; Gander, Sevecke et al., 2018). For future studies, recruiting an outpatient sample that might demonstrate a higher amount of secure attachment patterns would be helpful to conduct analysis using the 4-group classification. In this regard, some of our results show a p-value close to 0.05. However, there are two important aspects to consider: (1) Even though our sample size is not too small, it is also not very large, (2) our sample consists of adolescent inpatients with severe mental disorders. Including samples with less severe psychopathology (i.e. outpatient samples, community-based samples) might have increased the effect sizes and demonstrated greater p-values. Therefore, future studies including a sample with less psychopathology would contribute significantly to our understanding of attachment-related trauma and PD in adolescents.

Our study stands out as unique from previous studies as we used a large clinical inpatient adolescent sample to explore attachment status, severity of attachment trauma and childhood maltreatment in those with PD. Our findings do not only provide strong evidence for a high prevalence of over 20% for PDs in psychiatric units for younger age groups, but also for the presence of severe attachment trauma and childhood maltreatment in regard to physical and emotional neglect in these patients.

For clinical practice, our findings emphasize the importance of assessing attachment status and attachment-related traumatic material in adolescents with PD. This might help these patients to understand how their history of childhood trauma impacts their personality functioning on the interpersonal level and their affect regulation (Gander et al., 2020; George & Buchheim, 2014). Attachment-based intervention strategies might be particularly useful for them to face individual aspects of their attachment trauma (Gander et al., 2018a; Kobak & Kerig, 2015) and to develop more adaptive emotion regulation strategies in interpersonal contexts. In this regard, attachment-based interventions like the CONNECT program (Moretti et al., 2015), the attachment-based family therapy (ABFT, Ewing et al., 2015) or the MBT that is based on attachment theory (Beck et al., 2017) might be particularly helpful for patients with PD as they foster parental sensitivity and reflective functioning, dyadic affect regulation and mutuality within the parent-teen relationship. As suicidal ideation and suicide risk are common in patients with severe PD (Chanen, 2022), attachment-based treatments might be a useful approach because they demonstrated to more effectively reduce this behavior in teens than treatment as usual (Ewing et al., 2015; Waraan et al., 2021). A handful of recently published studies report that therapists that extensively use the attachment-based family treatment did not use standard CBT intervention techniques and that higher adherence to ABFT was related to positive treatment outcomes (Diamond et al., 2021). Furthermore, ABFT demonstrated higher rates of clinical symptom recovery and treatment retention in patients with suicidal ideation, major depression, anxiety and sexual abuse (Diamond et al., 2021). The findings of the present study might also expand on the use of psychotherapeutic techniques with adolescents. For example, a single case presentation of a 16-year old girl with BPD demonstrated how the use of attachment-related information from the AAP provided an insight into the patient’s traumatic dysregulation and helped to develop targeted therapeutic interventions supporting the patient to understand the emotional reactions to helplessness within an MBT setting (Gander & Sevecke, 2015). The integration of attachment issues in relation to unresolved attachment status and mentalization-based elements significantly improved the patient’s capacity to understand, interpret and differentiate between her own and other’s thoughts, feelings, desires and beliefs.

As empirically based treatments for PD in adults heavily rely on attachment theory (Buchheim & Diamond, 2018; Keefe et al., 2022; Levy et al., 2015), attachment-based treatment approaches hold the potential of a faster and greater symptom reduction, shortening the length of inpatient hospitalization and might yield better outcomes in regard to recidivism risk. The results of the present study might serve as a good foundation to optimize these therapeutic options for younger patients with personality pathology.