The ultra-high risk (UHR) criteria were defined to identify young people at high and imminent risk of developing the first episode of psychosis. Identifying UHR individuals provides an important contribution to clinical practice, facilitating the development of intervention strategies that can prevent the onset of a full-blown psychotic disorder. Nevertheless, UHR population is highly heterogeneous, displaying varying clinical conditions. This may undermine both clinical research and the assessment and treatment of patients. Therefore, it is essential to investigate which variables are involved in the development and maintenance of prodromal conditions in order to achieve a better diagnostic understanding and to improve the effectiveness of treatments. Several studies showed high rates of childhood traumatic experiences in at risk individuals (Mayo et al., 2017). Furthermore, there are pieces of evidence linking attachment adversity to the risk for developing psychosis (Russo et al., 2017) – an explanation may include enduring alterations of specific neurobiological pathways in children with insecure attachment (Debbané et al., 2016). Previous researches also highlighted the role of mentalization processes in moderating the risk of transition to psychotic disorders (ibidem). To date, attachment and mentalization have not been evaluated in HR patients using interview-based measures. The aim of this study was to explore the quality of attachment patterns, mentalization capacity and childhood traumatic experiences among UHR adolescents outpatients. Methods: 31 UHR adolescent outpatients were compared with 34 other outpatients who did not meet the ultra-high risk criteria. A multi-method/multi-informant diagnostic assessment was implemented, including the Structured Interview for Prodromal Syndromes/Scale for Prodromal Symptoms (SIPS/SOPS). The Adult Attachment Interview (AAI) was also administered, and the AAI transcripts were further assessed using both the Reflective Functioning (RF) Scale and the Complex-Trauma Questionnaire. Results: Although no differences between groups with respect to childhood traumatic experiences have been found, UHR patients showed a higher degree of insecure (χ2[1, N=65]=6.991; p=.008) and disorganized (χ2[1, N=65]=8.242; p=.004) attachment patterns. Moreover, the RF scores were significantly lower in the UHR sample (t=3.369; p<.001) and significant correlations between RF and any SOPS’ subscales were found. Conclusions: Our results underline the importance of taking both insecure/disorganized attachment and mentalization impairments into consideration when planning treatment for psychotic prodromal symptomatology. Our results seem to suggest that attachment-informed and mentalization-based psychotherapies may be effective preventive treatments for UHR patients. Debbané M, Salaminios G, Luyten P, Badoud D, Armando M, Solida Tozzi A et al. (2016). Attachment, Neurobiology, and Mentalizing along the Psychosis Continuum. Frontiers in Human Neuroscience, 10. Mayo D, Corey S, Kelly LH, Yohannes S, Youngquist AL, et al. (2017). The Role of Trauma and Stressful Life Events among Individuals at Clinical High Risk for Psychosis: A Review. Frontiers in Psychiatry, 8:55, 1-17. Russo DA, Stochl J, Hodgekins J, Iglesias-González M, Chipps P, Painter M, et al. (2017). Attachment styles and clinical correlates in people at ultra-high risk for psychosis. British Journal Of Psychology, 109(1), 45-62