• bipolar disorders
• CDS scale
• depressive disorders
• DES scale
• dissociation
• dissociative symptoms
• MOODS-SR
• SCI-DER
• spectrum project
• suicidality

Background: Today, the term "dissociation" is used to indicate different concepts, from pure dissociative symptoms associated transversally with a wide range of clinical conditions to actual dissociative disorders, discussed in a specific chapter of the DSM 5 and the more recent DSM 5-TR. In recent decades, dissociation has been described with a dimensional approach that places it in a continuum between normality and pathology, where symptoms can manifest themselves in a heterogeneous manner and with different intensity, in clinical and non-clinical populations. The association with some clinical conditions, such as Borderline Personality Disorder, Trauma-related Disorders, Anxiety Disorders or eating disorders is well documented in the literature, while studies on the prevalence of dissociative symptoms in the context of Mood Disorders have received more limited attention. It has also been highlighted that the presence of pathological dissociation is associated with a worse clinical outcome, as well as a potential increase in suicide risk or unsatisfactory therapeutic responses. Literature shows that patients with dissociative symptoms have more early traumatic experiences, comorbidity, early onset and suicide attempts. Delays in diagnosis and limited access to appropriate specialist treatment cause a decrease in quality of life and more disability. Diagnsosing dissociative phenomena may not be easy, especially when one is not faced with acute clinical presentation; they often represent a clinical dimension that is poorly investigated, already during the amnestic collection, also due to the cronicity of the manifestations that can lead the patient to keep quiet about them. Dissociative symptoms should therefore be assessed within the context of the usual psychopathological exploration, remembering both the importance of the link with traumatic and stressful life events and the fact that anxious-depressive syndromes could be secondary to a dissociative experience. In order to understand dissociative manifestations in all their nuances, it has been possible to apply the spectrum model in this area too, useful for highlighting even the mildest and low-grade symptoms, in addition to the subsyndromal pictures, which are nuanced and attenuated but still worthy of attention, since they can represent the prodromes, precursors or sequelae of a full-blown disorder. This approach can lead to significant clinical repercussions due to the frequent association between dissociative symptoms and other disorders, for example affective ones, for which an accurate and early diagnosis can be decisive in terms of treatment and prognosis. In this framework we tracked the presence of dissociative symptoms in a sample of subjects with bipolar disorder or major depressive episode (DB1, DB2, EDM), in which we also studied the presence or absence of suicidality. The aim of the study was to evaluate in these patients the correlation between dissociative symptoms and suicidality; it was also verified whether the presence of dissociative symptoms could represent a predictive factor.
Material and Methods: The original clinical sample included 156 outpatients, consecutively admitted to the Psychiatric Clinic of the University Hospital of Pisa. Our analyses were conducted considering 107 subjects of the 156 mentioned above, and therefore those who received a clinical diagnosis of mood disorder (DB1, DB2, EDM). The MOODS-SR questionnaire was provided to them to evaluate the responses to the items designed to investigate the presence of suicidal ideation and/or behaviour (Items 102-107). Three self-report scales were also administered looking for dissociative symptoms: the Dissociative Experiences Scale (DES), the Cambridge Depersonalization Scale (CDS) and the Structured Clinical Interview for the Derealization-Depersonalization Spectrum (SCI-DER). The data were entered into a database and all statistical analyses were performed using version 26.0 of the Statistical Package for the Social Sciences (SPSS).
Results: The Student's t-test for independent samples was used to compare the scores obtained by the two groups of subjects, with and without suicidality, in the various domains and in the total score of the DES, DER and CDS scales. Significant differences emerged in the subjects with suicidality in the total score of the three scales, as well as in some subscales/domains. Spearman correlation analysis revealed significant correlations between dissociation scales scores, total suicidality, and suicidal ideation. Linear regression analyses were also conducted; they showed a predictive effect of the first two domains of the SCI-DER scale on suicidal ideation and total suicidality, respectively.
Conclusions: Literature highlights that dissociative symptoms and suicidal risk are conditions that can frequently coexist and the results of our study reasonably support this evidence. In the components of our sample with a clinical diagnosis of DB1, DB2 or EDM, subjects with suicidality were found to be the majority. Furthermore, by administering self-report scales for the search for dissociative symptoms, significantly higher scores emerged in subjects with suicidality, as well as significant correlations between the scores on the dissociation scales and some of their specific domains, global suicidality and suicidal ideation. Finally, a predictive value of derealization and somatopsychic depersonalization emerged, always understood as scores on the respective domains of the DER scale, correspondingly with respect to suicidal ideation and total suicidality. This underlines the importance of using also spectrum instruments among clinical tools, validating the usefulness of a broader and more inclusive approach. Despite some limitations mentioned, this study is in line with the hypotheses that support the association between the presence of dissociative symptoms and a possible worsening of the disease course in clinical populations, as well as underlining the already documented importance of investigating and deepening the dimension of pathological dissociation, often unrecognized, in order to be able to consider and reduce the associated risks, optimizing therapeutic strategies.