Characterization of Bipolar Disorder I and II: Clinical Features, Comorbidities, and Pharmacological Pattern

Objective: Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition provides precise diagnostic criteria to differentiate between bipolar disorder (BD) type I and II; nevertheless, it can be challenging to come up with the right diagnosis. The aim of this study is to evaluate the sociodemographic differences, clinical features, comorbidities, and pharmacological pattern between patients with BD type I and II. Methods: A total of 680 patients with BD type I and II were consecutively recruited to our psychiatry department. A semi-structured interview was used to collect several information. Results: Patients with BD type I were mostly males, single, with a lower current age, and unemployed compared to patients with BD type II. Furthermore, patients with BD type I showed an earlier age at onset and a significant higher prevalence of psychotic and residual symptoms, a higher number of hospitalizations, and involuntary admissions. On the other hand, patients with BD type II were associated with a significant higher prevalence of lifetime suicide attempts, psychiatric comorbidities, and use of alcohol. Finally, antidepressant drugs were prescribed more often to patients with BD type II, while antipsychotics and mood stabilizers were mostly prescribed in patients with BD type I. Conclusion: the differentiation of the 2 nosologic bipolar diagnosis is in line with the current scientific interest, confirming the existence of a markedly different profile between BD type I and II. This differentiation could reduce the heterogeneity of bipolar presentation in research, optimize clinical assessment, and increase the interest in developing more precise and individualized therapeutic strategies, also implementing psychosocial therapies.