The influence of mental and somatic multimorbidity on suicidal tendencies in patients with affective disorders

Background. Suicidal tendencies are a serious problem in patients with affective disorders. The role of multimorbid-ity in the formation of suicide risk requires clarification taking into account the nosological specificity, especially when comparing bipolar affective disorder (BD) and recurrent depressive disorder (RDD). Objective. To assess the impact of mental and somatic multimorbidity on suicidal tendencies in patients with bipolar disorder and RDD and to identify clin-ical characteristics associated with their increased risk. Material and Methods. The cross-sectional multicenter study included 182 patients according to ICD-10 criteria (F31.0 BD ‒ n=139, F33 RDD ‒ n=43). Diagnosis was made using the Mini-International Neuropsychiatric Inventory (MINI). The Columbia Suicide Severity Rating Scale (C-SSRS) was used to assess suicidal tendencies, and the Montgomery-Asberg Depression Rating Scale (MADRS) was used to assess the severity of depression. Statistical analysis was performed using nonparametric tests in R. Results. Patients with bipo-lar disorder showed a statistically significantly higher frequency of psychiatric multimorbidity compared to patients with RDD, primarily disorders related to alcohol use (p=0.003) and harmful substance use (p=0.038), as well as eating disor-ders (p<0.05). In contrast, posttraumatic stress disorder was statistically significantly (p=0.044) more common in the RDD group. The presence of psychiatric multimorbidity in patients with bipolar disorder was associated with statistically significantly higher rates of suicidal ideation (p=0.002) and behavior (p=0.004) throughout life, as well as with a higher actual number of suicide attempts (p=0.0005), whereas no such association was found in patients with recurrent depres-sion. Somatic multimorbidity did not have a statistically significant effect on suicide risk in either group of patients. For the bipolar disorder group, a weak statistically significant negative correlation was established between the age and the number of suicide attempts (rs=-0.29, p=0.0005), as well as between the age of disease manifestation and suicidal behav-ior (rs=-0.18, p=0.038). A statistically significant moderate positive correlation was found between the severity of de-pression on the MADRS scale and current suicidal ideation (rs=0.590; p<0.001) in the overall sample. Conclusion. The impact of multimorbidity on suicide risk is differentiated depending on the underlying diagnosis. Mental multimorbidity is one of the key factors of suicide risk specifically in bipolar disorder, which justifies the need for targeted integrative care for this category of patients. In recurrent depressive disorder, suicide risk is apparently mediated to a greater extent by the current affective state than by the multimorbidity structure. The obtained data emphasize the importance of differentiated assessment and prevention of suicidal behavior, taking into account the nosological specificity and multimorbidity profile.